johnsmachines

machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment. I read every comment and respond to most. n.b. There is a list of my first 800 posts in my post of 17 June 2021, titled "800 Posts"

June 23, 2017

If at first you don’t succeed…

Try again.

The small reversing handle lock on the horizontal mill engine took 4 attempts.

Most of the components are made. That is my blood staining the plans.

The lock is made of brass. About 32mm long, then bent into shape.

From the left.. 1. broke when turning the thread. 2, cracked during bending, not enough heat. 3. Too much heat melted the surface. 4. Success.

And on the same subject, the cylinder head and guide went well until I neglected to remove it while finishing the guide block.

I might have mentioned this one previously. It still rankles.

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June 20, 2017

Another Diversion from The Triple

My model engineering club (GSMEE) has an annual competition build. This year it is a small horizontal reversing steam engine.

So I have taken another break from the triple to build the HME. I have redrawn the plans to make my model 40% bigger, and also to accept metric fasteners.

The HME blanks for the base, the cylinder block, the flywheel pillar and the flywheel. The only stainless steel I had in my junkbox, er storage facility, had a big hole in the middle, so I filled that with brass.

All was going well, and I spent almost a day making the piston head guide. Then finished off by making the guide rod and block. I decided to take another thou off the guide block, and set the lathe going.

And heard an ominous bang.

I had forgotten to remove the piston head guide from the from the piston before I restarted the lathe. Destruction. The lump at the bottom is another piece of brass, ready to be turned into another head guide. I had run out of suitably sized brass, so I silver soldered a length of rod to some square section. A day later and the new piston head guide is now made.

At least I know from this (and other crashes), that the second part is always made much faster than the first.

And on a different subject, I recently bought on Fleabay a self centering 4 jaw chuck.

It does not replace the independent jaw 4 jaw chuck for accurate work, but will be useful for turning small square stock. Also, I plan to make a backing plate for it to fit into the tailstock, so it will hold taps.

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June 8, 2017

A Base for the triple, and some oil holes…

Thinking about the options for a base for the triple expansion marine steam engine..

I looked at every photo I could find on the net, and thinking about whether I want to be historically accurate, or just really solid, or a bit interesting with an historical flavour.

At this stage, the decision is not set in concrete, but I am going with the last option. Photos later in this post.

But first, I have pulled all of the major components apart, and I am spending time doing a few of those jobs which I had been avoiding because they are difficult and imprecise, and if they go badly it will be a major disaster at this stage. Like drilling the oil holes and wells for the big ends.

Nothing precise about this. The con rods and big end shells and bearings have been painstakingly machined, and I do not want to think about remaking them if I stuff up. And drilling into curved surfaces, with a 1.5mm drill bit…

That thread is 3mm dia. The hole above the nut is the oil way, 1.5mm dia. Very tricky and too anxiety provoking to be thinking about a video. Amazingly, it all went well! I now have 2 oil holes for each of the 3 big ends. I will need to fill the well with oil with a medical syringe and fine needle, but.

The crankshaft, turned from stainless steel a year or two ago, and the conrods. The big ends now with lubrication points.

And here are the major engine components, after partial disassembly.

At top left is the condensor, then the cylinder block in 2 parts, then the steam supply valve. The square section tube is going to become the base. And so on. You get the picture. I will count the bits at some stage.

Then I cut and drilled the square section aluminium tube for the base.

The cast base of the triple, with main bearing studs and column studs in place. All sitting on the square section alu. Have not decided whether to bolt it together, or just Loctite it.

Those holes in the square section were drilled and chamfered on the CNC mill.

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May 27, 2017

Making Hubcaps

I made 5 of these

The 50mm diameter aluminium blank had a 12mm bolt inserted into a blind threaded hole. The bolt was held in the lathe chuck.

The 2 short videos which follow show 1. the final rough cut 2. the finish cut.

The shape was drawn as a DXF file using CAD, the G code was generated using Ezilathe, and the lathe was controlled with Mach3.

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Total CNC turning time was 16 minutes per hubcap, plus cutting the groove for the O-ring, then a quick polish with a cleaning pad.

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May 23, 2017

Chariot Racing

Another little job for my CNC lathe.

A fellow club member asked me to turn some hub caps for his car restoration. And the shape was a bit unusual.

This is the first effort at complying with his request.

It is aluminium, and will be held in position with an O-ring in the groove.

If I had put a knife edge on it he could have justified new car number plates…..

BEN-HUR

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May 19, 2017

Metalworking for a cabinet maker

Our model engineering club has been locked out of our club rooms because MOULD has been detected in the building. Apparently a lengthy process to reduce the mould to acceptable levels. (note to self…. make sure that the inspectors never set foot in our house).

So our meetings have been held in various locations, including a sports centre and a basketball building. I feel quite virtuous when I enter these buildings, but for some reason I do not feel any fitter when I exit.

A recent day meeting was held at my farm workshop. Not my farm anymore, just the buildings.

Not that one…. the other one.

And one of our more senior members requested a display of CNC machining, from design to product.

So, I drew up a finial which was required to complete a bookcase which I had built 30 years ago. Then imported the DXF drawing file into “Ezilathe”.

Showing Stuart Tankard, the author of Ezilathe, scrutinizing my drawing …. and offering excellent suggestions for improvement using Ezilathe.

Then used Ezilathe to generate the G codes…..

Then to the CNC lathe…..

CNC turning the finial in 51mm brass rod. 1600rpm, 100mm/min. Controlled by Mach 3 Turn. I removed the tailstock shortly after this photo was taken, to permit completion of the ball.

Some GSMEE members watching the CNC turning. I spent 3 days clearing up the workshop so the 16 members could fit in. Amazing how much space was revealed in the workshop. This is the Taiwanese lathe which I converted to CNC. See old posts for details of the conversion.

I watched anxiously as the part was gradually revealed. Admittedly, I had had a test run in wood to check the parameters, but this was the first run in metal.

The finial. The bar stock was parted later.

Bookcase finally finished, after 30 years.

If you are interested in CNC lathe work, you should take a look at “Ezilathe”. It is superb.

If you are on Facebook, (of course you are if you are reading this), you might like to take a look at the GSMEE Facebook site.

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April 24, 2017

Arduino Controlled Indexer-2

Most of the bits and pieces have arrived for this project, so I made a start on the machining today. I used 80mm dia aluminium rod to make the stepper motor support piece.

Stepper motor (right), flexible 8-12mm shaft coupler, and the rotary table shaft (left)

I cut a 92mm cylinder of aluminium, squared the ends, centre drilled a face, drilled it out to 25.4mm, shown in this photo. Note the 4 ribbons of swarf coming off the work. The drill bit is an industrial stepped bit, with 4 cutting lips. Then the hole was bored to 28.80mm.

An upside down photo of the stepper motor (left), motor support which is hiding the flexible shaft coupler, and rotary table (right). Next to drill and tap for the bolts, and provide access holes for the coupling screws.

And some more milling to convert the cylinder to a rounded square section, then drilling and tapping for the grub screws and bolts for the stepper motor. (tapping with the Mogens Kilde tapping head in the picture).

The finished support block

Mechanicals finished. Now for the electronics.

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April 21, 2017

Triple Expansion Steam Engine Pipework.

I am close to disassembling the Bolton 9, before gradually reassembling it in preparation for running it on air then steam. Most of the components have now been made. Most recently I completed the pipework associated with the Edwards air pump and the twin water pumps.

This is the combined air and water pumps, and new pipework. Most joins are silver soldered, but a couple are Loctited. Loctite should be adequate. These components will not get super hot.

This valve is one of the few components on this engine which I have not personally made. This one came from the effects of the late Harry Close, who was a valued member of our Model Engineering Club.

The pipework adds to the overall interest , yes? It will look good when polished.

And the “tails” for the valve rods, which are attached to their respective steam chests. The BA7 bolts are a bit oversized for the job. The intermediate cylinder tail screws into place. I am not sure why it is different from the other two.

So now I am making a list of tasks which need to be completed when the engine is taken apart, hopefully for the last time before it is run. The list is not complete, and so far it runs to 3 pages. Mostly like fixing parts which interfere with each other, and freeing up tight bearings.

I will take some pics of the components.

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April 15, 2017

Cutting a thread up to a shoulder

A problem with some thread dies is that they have such a large “lead in” that they are unable to cut a thread up to a shoulder.

A 3/8″ x 32tpi die. Note the large lead in taper.

This results in the thread stopping a long way from the shoulder… undesireable in some situations.

This is a thread made with the die in the previous photo. I wanted it to go right up to the shoulder, but this is as close as it gets. About 2mm gap.

The screw in this upsidedown photo does not allow the shoulder to seat properly.

The solution? Modify the tool.

Here is the tapping die, held onto a magnetic chuck, within a machined steel disc to increase the magnetic attachment force.

So I ground off the top 1-2mm of the die. My surface grinder is out of action, so I used the tool and cutter grinder. A bit rough but it worked.

This is the die after grinding the surface. Note that there is no lead in. I ground the unlabelled face so I did not lose the specs of the die.

And the screw after using the modified die. The thread now goes right up to the shoulder. Incidentally, this is a zoomed photo using an iphone. Not bad?

So that does the job.

The downside is that in future the thread must be started with the unmodified side of the die, and finished with the modified side. Adds some time. And the die is thinner and a bit weaker.

A pity that the dies are not manufactured with one “no lead in” face.

The particular set of ME dies will now all be modified in the same way.

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April 7, 2017

A Turntable for the Triple Expansion Engine.

I have not weighed the Bolton 9 triple expansion steam engine, but I would guess that it is 20-25lb. (weighed it. 25.5lb)

Access to the various bolt on bits and pieces has become increasingly difficult and tricky, and involves frequent repositioning of the engine.

I removed the bolt on base and that has improved the situation a bit.

Then I had a brainwave, thought bubble, inspiration whatever, and I tried a ball bearing turntable…. you know….. one of those Chinese restaurant middle of the table gadjets.

It is incredibly useful!

Here are some pics and a video showing it in place; just a demo of the engine at its current (unfinished) stage. I think that the turntable might become a frequently used tool for heavier models.

The Bolton 9 on the turntable

And the latest additional bits… non return valves on the water pumps.

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April 3, 2017

Project in the Wings.

While finishing the triple expansion steam engine, I have decided on my next project. Actually, based on my past history of procrastination with the triple, I might even put aside the triple to start on this one.

Reading this article in “Model Engineers’ Workshop” gave me the inspiration to convert a rotary table to electronic control.

Dec 2016 MEW article

So I have commenced accumulating the bits and pieces…

An 8″ Vertex rotary table. I have had this for years, but unused since acquiring a universal dividing head. Should be ideal for this project.

A Nema 24 Stepper motor, shafts at each end, so I can use the table manually as well as electronically. The Microstep driver was supplied packaged with the motor as a kit. $90AUD inc postage.

From the same supplier, a 48volt power supply. $38AUD

The brain of the system. A programable microcontroller “Arduino Uno”. I bought 5 of these for $20AUD post included.

And an easily attachable display. To attach the Arduino. $19AUD

And since I knew nothing about Arduinos, a “Getting Started” book. Excellent. On loan from a friend (thanks Stuart)

And to practice some circuits and get some idea about the Arduino programming, a starter kit of bits and pieces. $75AUD, but has been very instructive and loads of fun. The program to run the Arduino is downloadable free from the Internet, so this kit might be a bit superfluous.

And some items of kit. Each under $20AUD.

A magnifier soldering station, and head light and magnifier

A very cheap multimeter. Previous purchase. Works fine. $10AUD

I have disassembled the rotary table, and ordered a 12/8mm coupler. I am waiting for the coupler before I start designing and cutting the main part to be fabricated which is the piece which joins the stepper and the table.

Also ordered a box to contain the electronics and switches. Havn’t yet thought about cables, joiners etc.

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April 2, 2017

Edwards Pump for the Triple Expansion Steam Engine

The triple expansion steam engine has been progressing, again. I started this project over 2 years ago, but I have taken many breaks, some prolongued. One break lasted over 6 months while I made some cannons.

I cannot remember when I made the Edwards pump for the triple, but it must be over a year ago. In the past few days I have returned to it, finalising the mounting to the engine, and joining the driving levers to the pump and the engine.

The Edwards pump creates the vacuum in the condenser chest. It is an air pump.

Attached to the Edwards pump are 2 water pumps, which return condensed steam as water, to the boiler. At least that is what I understand from the descriptions. It feels a bit odd, making these components before understanding what they really do.

The Edwards pump is the central cylinder and rod. The water pumps, bolted to the sides, are just lumps of semi machined cast gunmetal at the stage this photo was taken.

The step before the above picture, where the base of one water pump is machined.

The Edwards pump, and the 2 water pumps, almost finished, attached to the engine.

There is no clearance between the pump gland and the condensor, so the intitial hexagonal glands which I made (not shown) were unuseable. So I made these cylindrical glands which required a tiny hook spanner to tighten. The hook spanner was made on the CNC mill from 1/8″ brass plate. A little filing was required to shape the hooked tooth. Works nicely.

The pump unit, lower left, attached to the engine. Actuating levers driven off the low pressure cylinder (not yet connected).

The pump unit viewed from the side.

So I am at the stage where I would like this project to be finished, so I can get on with other projects. It feels like it is close because there are very few castings remaining in the box. But I know that the entire engine has to be disassembled, and painstakingly reassembled, freeing up some of the tight parts so it will turn over more easily. Then the steam pipe hookups and valve timing. Then hopefully, a video of it running!

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March 25, 2017

NEW SPINDLE MOTOR for CNC LATHE?

Now that I have replaced the stepper motors in the Boxford CNC lathe, (see “New steppers for an old CNC lathe”) I am considering whether I might replace the spindle motor for the same reason… that it has become less powerful due to the age of its permanent magnets. Sometimes I am aware that it struggles to keep up the revs while cutting.

Watch the YouTube video about the next generation servo motors. They use modern rare earth magnets. They are powerful, compact and precise. And not cheap. Stuart T, who has the same Boxford CNC lathe as me, has suggested that these Clearpath motors would be suitable replacements for the ageing Boxford spindle motors .

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March 24, 2017

Harold Hall Grinder Rest – modification; and triple expansion update.

Harold Hall has written many articles and several very useful books about metalworking, using a lathe, using a mill, and much more.

Recently he has been posting videos on YouTube.

He is a very knowlegable, dignified, elderly gentleman. His books are precisely, beautifully written, and the plans and projects are excellent. I have made quite a few of the project pieces in my quest to learn as much as I can about machining metal.

I came across his Youtube videos quite recently, and have been enjoying them. One of them was about his grinding rest.

I made 2 of the HH grinding rests from plans in his book, and they have proved to be useful, reliable, and compact. Here is a photo of one of them.

The original HH plans specify that the footprint of the base is much smaller than I made it. This one is 200 x 100mm. The larger footprint adds some extra stability (IMO), and the slots permit the grinder to rest distance being easily adjusted. It is a bit grimy because it is used frequently. Polishes up quite nicely.

In HH’s video he mounts the rest on a metal plate, joined with a couple of switchable magnet bases. Here is a link to HH’s Youtube video.

And in case you are wondering what has happened to the triple expansion engine, I have been working on the reversing mechanism. The intermediate cylinder reversing curved slide would not fit into the available space, so I removed it, silver soldered in a new end, and ground it several millimeters shorter. Then reinstalled it. It is still a mm or so too long but I think that it will do.

The high pressure reversing mechanism on the right, and the intermediate hiding behind, on the left of the pic.

The intermediate cylinder valve rods and eccentrics. Rather difficult access.

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March 5, 2017

The Robert the Bruce approach to turning problems.

Robert the Bruce was watching a spider making a web in the cave they were sharing, so the story goes. The spider tried 6 times to make a difficult connection, and on the 7th attempt, it succeeded. Robert, who had tried many times to become king of the Scots, was inspired to try yet again, and he did indeed become King Robert 1 of Scotland, eventually.

I thought of Robert more than once recently, when I was making an ER40 collet chuck for my CNC lathe. The particular collet chuck involved making a 2.25″ x 8tpi internal thread, a 50mm x 1.5mm external thread, and cutting an 8 degree internal taper. Not too complicated you say. I agree, but for the chuck to be useful, each step had to be extremely accurate.

I made 4 successive collet chucks until one was adequately accurate.

CHUCK 1, 2 and 3

Chuck 1 actually went very well. Nice tight spindle thread, taper good, and external thread just right. But the chuck did not quite seat firmly. Could it be that the spindle thread (the internal one) was not quite long enough? So I cut a deep distal groove. Wound out the carriage. Oh shit! Forgot to clear the spindle thread. Totally destroyed it. The chuck actually fitted the spindle quite nicely, but with only 10% of the thread remaining, it was useless.

Chuck 2 was made in 2 pieces, on suggestion from Stuart T. The idea being that if there was any inaccuracy in the lateral runout, the piece with the taper could be adjusted. OK. Sounded sensible. Again all went well, but the spindle thread was not correct. For some reason the thread cutter seemed to make a new path about half way through making the thread. So the spindle thread was thinned excessively. But still tight. So I made the tapered half, and joined it all together. Fitted it to the lathe and measured the runout and taper. All good. Less than 0.01mm runout and perfectly parallel to 100mm from the chuck face. But. The next day I removed the chuck, replaced it, and did the runout measurements again. I did not need a gauge. I could see the wobble. Chucked the chuck into the rubbish bin. That thinnned out spindle thread was hopeless. But what caused the problem? The thread was CNC cut, and it should have been perfect.

So chuck 3. One piece again. All seemed to go well, but again the big spindle thread was wrong. Again there seemed to be 2 thread paths.

Then the penny dropped. The spider made the web connection. Robert got the throne and John saw the light.

The tool post had moved slightly during the threading! It had twisted a little, as a result of the T piece in the carriage slipping. F**K F**K F**K!!!

I replaced the T piece grub screws with more solid cap screws, and really tightened them. Then made another chuck. I must point out that each chuck was about 6-8 hours of machining, normally a very pleasant time. But by this time, I felt like that bloody spider in the cave.

ER40 Chuck Number 4.

One advantage of making 4 chucks is that each one was made faster, and with more confidence. This one was made in about 5-6 hours, including painting with selenium oxide to give it a black appearance.

It has a runout at the chuck face of 0 – 0.01mm (which might have been due to inaccuracy in the rod which was being measured), and a taper of 0.02mm at 50mm from the chuck face. It feels nice and tight when being screwed on. OK, Success. Eventually.

Next job, the throne of Scotland.

But obviously that slipping top slide on the CNC lathe has to follow chucks 1,2 and 3 into the rubbish bin. It will be replaced by a fixed, immoveable tool post.

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March 5, 2017

New Steppers for an old CNC Lathe

My Boxford TCL125 CNC lathe was missing steps in the cross slide, with resulting inaccurate work. Obvious causes, like cutters not sharp, or gibs too tight were excluded. Changes in the stepper motor settings maybe helped a bit, but not enough.

Stuart T suggested replacing the stepper motor, since the machine is a 1985 model, and the steppers look original, and therefore the 32 year old stepper permanent magnets are probably not as strong as they were originally.

We had changed the electronic controls in the lathe 3 or 4 years ago, so it would work with a Windows PC, and Mach3. Mostly I use “Easylathe” for generating the G codes.

Stuart had a spare stepper motor in his junk box, and it was the correct size (Nema 23), but more powerful than original. So I swapped it, and missing steps disappeared. Hooray! A minor problem was that Stuart’s stepper had shafts at both ends, and I was not comfortable about cutting off the unwanted shaft end, and I had decided to change the Z axis stepper also , so I ordered some new stepper motors.

A carton of 3 motors arrived a few days after placing the order. They are made in China, and are nicely finished. Each new motor had 4 wires, whereas the originals had 8 wires each, but reference to the wiring diagrams quickly determined the connections. Total cost for the 3 motors was $AUD90, including postage, and now I have a spare.

A big advantage of the NEMA mounting system is that the motor mounting dimensions are fixed, so swapping motors is simple. More powerful stepper motors are longer, but the dimensions are all available online, and can be checked before ordering.

The black and silver new stepper motors fitted to the Boxford TCL125. One cover waiting to be reinstalled.

The old steppers on the right.

A simple CNC turning test worked well, so I am hopeful that this problem is fixed.

4 Comments

February 25, 2017

Swap Meet Bargains

Yesterday I travelled to Ballarat, (Victoria, Australia) to a swap meet which was held on 22 acres at the airfield.

Most of the stuff in the thousands of sites, was junk from shed and farm cleanouts. However, despite rapidly walking up and down the rows, I did not quite cover all of the sites. My Apple watch indicated that I had walked 18km (11.2 miles) and much of that was carrying a backpack full of bought items, so it was no wonder that my ankles were aching at the end of it.

I was really only interested in the few sites which had tools from factory closures. But my eye was drawn to the very old Caterpillar crawler tractor, a 2 tonner, not too derelict except for a broken exhaust manifold and some rusted growsers. $AUD9500, so I kept on walking. Lots of elderly, old and antique cars, motor bikes, and vehicular bits and pieces.

The following photos show most of the stuff which I bought, and some prices (except for the ones which SWMBO must never discover).

A Japanese woodworker’s chisel. 9 mm wide. Razer sharp, oak handle. I buy one of these at each Ballarat swap meet from the same seller, a lovely Japanese woodworker who lives and works in Victoria. These chisels are a pleasure to use. $AUD25

This was a bargain. A set of good quality English BA open ender spanners, probably unused, for $AUD8

I dont know what this is called, but it has an INT40 taper, and bolts to the workbench or mill for inserting and removing cutters from the toolholholder, and avoiding the cutter dropping down and being damaged. Is it a tool setter? Anyway, $AUD40

Used but sharp, quality brands. Carbide ball nose end mill, countersink bit, T slot cutter, and 1/4″ BSP spiral tap. $AUD30

A new, interesting woodworking cutter, carbide, with left and right hand spirals to avoid surface furring. $AUD10

3 Mitutoyo telescoping gauges. $AUD10

I mulled over a Mitutoyo 1000mm vernier caliper in perfect condition for $AUD300, but decided that it was a wanted rather than needed item, and walked on.

A box of 12 brand new quality Wiltshire triangular files. $AUD12

2 very nice Moore and Wright thread gauges, which have BA and Acme threads as well as metric and Imperial angles. $AUD6

A box of metric counterbores. Not cheap, but good price considering the German quality, and condition. $AUD55

Small die holder, Sidchrome 10mm spanner, tiny Dowidatadjuster and new box of inserts. All useful. About $AUD45

Chesterman vernier height gauge. Unusual triangular column. Beautiful condition, complete range of accessories, in a lined box. Metric and Imperial. Price not to be dislosed to SWMBO.

These are brass wick type oilers which I will give to the local Vintage Machinery Society. No markings.

My brother was a navigator in the Australian Air Force many years ago, before the age of satellite navigation. He would sight the stars using a sextant something like this to calculate the plane’s position, while standing in a glass dome in the roof of the aircraft. (I think that I got that description approximately correct). He once told me that he would like to have a sextant again, so when I spotted this at the swap meet, and the price was OK, I decided to get it for him. Maybe it will make up for all of those forgotten birthdays. So little brother, leave some room in your suitcase when you next visit. I will leave the clean up and renovation to you.

Elliott Bros London.

It looks fairly complete and intact. Of course I have no idea how it works.

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January 15, 2017

Assembling the Triple

I got this far in assembling the model triple expansion steam engine, then lost courage and put it aside (again). You can see the high pressure steam chest labelled “top”, the steam valve and handle, the drag links and levers for the reversing mechanism for the high pressure cylinder, and the worm and gear and control wheel for the reversing mechanism. The reversing levers will need pinning with taper pins when the correct positions are finalised. The short rod in the middle of the pic is temporary. I need to make those properly. The drag links clash with the condenser cover. That was predicted in Bertinat’s notes. The cover will need some material removed. Slowly progressing, but taking frequent breathers.

The high pressure mechanisms are the most exposed, and easiest to access, and they were very tricky, and not yet compeletely installed. I dread to consider what the intermediate pressure ones will be like, buried in the middle of the engine. Then there is the valve timing. Help!

4 Comments

January 14, 2017

A Full Size Weighshaft

The crowds were down at this year’s Truck Show at the Geelong Showgrounds. Maybe the 38c weather prediction had something to do with that.

But those hardy souls who did turn up were treated to a feast of steam engines working on steam, and other antique engines popping away, as well as the magnificent trucks, tactors, and military vehicles. There was a superb display of radio controlled trucks and excavators, and unbelievable machinery created with Meccano.

My interest was mainly focussed, for some reason, on the full sized triple expansion steam engine, which is the prize display in the vintage machinery shed. it once powered a tug boat, and later a dredge on Port Phillip Bay. And the following photos and video, if it will upload, show the bits which were of particular interest.

The red control handle top right is the main steam control valve. The one on the left is the reversing control handle. Note the big steam piston centre bottom. It is a steam powered reversing control piston. This engine was made in 1951, so is just about the last gasp in triple expansion steam engine development.

and the rod at top is about 5″ diameter. It is the weighshaft, which carries the reversing levers for each cylinder. On my model it is 5mm diameter.

Another view of the weighshaft and the levers. Massive.

And note the drag links in the adjustable block. That would have been set at intitial installation, and probably never altered since then.

Video of the big triple expansion engine working. Maybe not.

For those following my triple expansion steam model engine build, I have put it aside again. It is at the final assembly stage now.

Meanwhile, I am making some extra tool holders for the CNC lathe, and another ER40 chuck for the CNC lathe.

The ER40 chuck which I am currently using has an M5 shaft which is held with a drawbar, so I cannot feed work through the lathe spindle. Plus it sticks out of the headstock a bit excessively. So I have drawn up plans for a new chuck which I will fit to the lathe spindle and use the CNC to make the ER40 taper and threads. Pics will follow.

And I really need some extra tool holders for the CNC lathe. I have 5, but have material to make another 10. The material is high quality cast iron off a scrapped T&C grinder. I bought the grinder table cheaply (($AUD20 from memory) and have been gradually canibalising it over the last couple of years. I have cut up the remains into rectangular 30x80x40mm chunks and will make the tool holders in the next couple of days, SWMBO and weather permitting. Unfortunately there was insufficient material to make a long section, machine it, then cut it up, so each tool holder will have to be made separately.

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January 7, 2017

Anyone for a swim?

High summer.

Hot workshop, wearing only shorts and boots.

I think that I will stay in the workshop.

Today was my deadline to have the triple expansion steam engine assembled and working, ready to be hooked up to steam at the Geelong Truck show.

GSMEE (Geelong Society of Model and Experimental Engineers) has a display in the Vintage Machinery Shed at the show, with many small working steam engines and the odd IC engine running. Plus the Vintage Engine group has many full size engines running…. always a really interesting place to visit.

Another full day in the workshop would have just about had the triple in the display. Unfortunately, I lost a day having to get a dental root canal abcess reamed out.

Then the day before yesterday, I could not find the drag links for my triple. I had made them in early December, and I was sure that I had put them in the multi- compartmented box where I store all such bits. Despite thoroughly searching the box, at least 20 times, they were not there. Could I have put them down somewhere else in the workshop? So I searched the workshop. No luck. So I tidied the workshop, putting tools away, sweeping up rubbish, all the while searching. Still no luck. So I cleaned and searched my car, my bedroom, the living room, every where that I could concievably have left them. (OK, I did not actually clean the bedroom and living room, but I did search). I grilled my wife. Had she seen them? No.

So I slept on the problem. Next day was going to be hot, so at 7am I drove to the workshop (it is about 15km from home), and searched again. Still no luck.

So I searched the multi compartmented box for the 21st time. I knew that it was a waste of time, but I was seriously considering making a new lot of drag links and bearings, probably a 2 day task.

There were some tiny containers with tiny fasteners in the compartmented box. The drag links could not be them because they are too big, aren’t they…..??

The first tiny container, contained, you guessed it, the drag links.!! They were smaller than I remembered.

Relief!

Self disgust!

Age related loss of short term memory…..

I had to get that one off my chest.

The other thing that I wanted to mention, is a superb machining blog site. Actually, 2 superb machining blog sites.

The first is by Joe Pieczynski, who is a Texan who makes his living from machining. His techniques and teaching are really, very, excellent. Aimed mainly at an audience who are beyond absolute beginners. Do a Youtube search on “Joe Pieczynski”. Look at his video on machining ultrathin materials.

The second, I have probably mentioned before. An Australian machinist, whose videos and machining techniques have to be seen to be believed. Mainly with a clock making interest, but the techniques can be used by all of us. For some reason I cannot cut and paste his Youtube connection, but you will find it by doing a search on “Clickspring”. What is particularly exciting in Chris’s “Clicksping” is that he is soon to embark on remaking an Antikythera calculator. Watch it! You will be hooked.

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January 4, 2017

The Steam Supply Valve

This valve is the one which opens the steam supply from the boiler to the engine. Triple expansion sgeam engines require a minimum of 100 psi, and preferably 120-200psi. But amteur built boilers are rarely certified above 100 psi.

But compressed air gets to 120 psi with no drama. So guess what will power this engine until I get around to making a high pressure boiler.

So the on-off valve needs to be pretty solid, so it does not explode and send hot fragments of metal in all directions.

Here is the main supply valve as specified and built for my triple expansion steam engine.

The lines in the background are a ruled exercise book, just to give a sense of the scale. There are 9 components of precision machined components in this picture. And about 2-3, 8-12 hr very happy days in the workshop to make. This is all made from bar stock.

And this is the handle which controls the on – off steam supply. Pretty sexy hey?

It all attaches to the high pressure steam chest and cylinder.

Hey! I like this ~~shit~~ stuff . Even if most of the rest of humanity is yawning.

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January 2, 2017

SS Valve Rods

Making the new valve rods, as predicted, took me an entire day. They required a high degree of precision, and being in stainless steel, not an easy material to machine, and quite thin and delicate, multiple stages in the machining.

But before I started on the valve rods I made myself a new spanner for the collet chuck on the CNC lathe. I had been using an adjusting spanner, which was continually going out of adjustment and causing angst. The tool merchants did not have anything suitable (46mm opening, and thin profile), so I made my own.

The 46mm spanner being cut from 6mm steel plate.

It is a bit prettier after this photo and being painted. The rounded jaws facilitate easy application to the collet chuck.

Tightening the ER40 collet chuck with the new spanner. It works very well.

So then I got on with the new valve rods. Some end of day photos follow.

The valve rod is the silver coloured rod. Actually stainless steel. This photo shows the high pressure cylinder valve and valve chest. There are 2 other valves, one for each cylinder. All different sizes.

The high pressure valve chest and valve, the valve rod and guide. On the right is the Stevenson’s link, yokes and eccentrics which control forward and reverse. This setup is repeated for each of the 3 cylinders. This is hooked upto the worm and gear which was shown a blog or two ago. There are 22 components for each, not counting fasteners.

The low pressure setup.

And thank you to those readers who responded to my whinge about likes and comments. I will continue this blog until the triple expansion steam engine is finished, and hopefully running. Not sure after that.

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December 31, 2016

Triple Underbelly

“Underbelly” has a particular resonance for readers who know what the Yarra is and that Collingwood is a place and not a British admiral.

In the instance of my triple expansion steam engine, it refers to the bits and pieces underneath the cylinder block. The glands which prevent steam leaks from the con rods and steam valve rods, the and valve rod guides. These unsung heroes of the steam engine have taken 2 entire days to make. And here they are….

This is the cylinder block, upside down. You can see the valve rods. the valve rod guides, the valve rod glands, the piston rods, the cross heads (unfinished), the piston rod glands, and the cylinder bases. Give yourself 2 marks for each correctly identified item. The 6 hex plugs on the side are temporary, until I get around to making some cylinder drain valves.

I started to count the number of holes drilled and tapped in this view, but gave up at 100 and still not half way. This engine better bloody work!

Note the letter stamped into the cylinder base. Many parts are similarly stamped. The studs in the intermediate piston gland are temporary.

Just a different view.

I have decided to replace the valve rods which are made of brass, with stainless steel ones. That will take an extra day, which might exceed my second, self imposed, deadline. But if it does, well too bad.

By the way…. I am considering whether or not to continue this blog. It does take time, and is not free. If you read this and are not totally bored, the odd “like” would not go un-noticed. A comment would be even better.

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December 27, 2016

Reversing Gears and Handwheel

Another 2 days in the workshop. Heaven.

I had made a worm drive and gear using an M14 x 2 tap, but it did not look the part, despite being functional. The problem was that the threads were sharp triangular and they did not look correct.

So I made a worm drive and gear using Acme specifications. The teeth have a chunkier squarish look. More authentic.

I ground a lathe cutter and used it to make the worm drive in gunmetal, and another identical thread in 14mm silver steel (drill rod). The steel thread had cutting edges formed, and when finished it was hardened by heating red hot and quenching. After hardening, a file would not mark it. I did not bother to anneal it, since it would be used only to cut cut brass or gunmetal. The hardened tool was used to make a gear in gunmetal. Unfortunately I did not take pictures of those steps.

Showing the handwheel, worm drive and gear. the shaft is mounted in gunmetal bearings which are bolted to the columns with BA8 bolts. The thread is Acme. 2mm pitch. The handwheel will control forward-reverse of the triple expansion steam engine.

In order to determine the position of the bearing bolt holes for the worm drive, I used SuperGlue to tempararily join the worm and gear.

When the position of the bearings was determined, the holes were drilled 1.8mm and tapped. the taps were BA8, about 2mm diameter. The engine is held vertically on the milling table, being cramped to a large angle plate. The holes were drilled accurately on the mill. The threads were made using a tapping head made by me from plans published in “Model Engineer” by Mogens Kilde. The double parallelogram of the tapping tool keeps the tap vertical. The tap did not break.

Close up photo of tapping the BA8 threads. Showing the bearing, shaft, worm drive and gear. Note the Acme thread. The bearing is Super Glued into position to facilitate the drilling and tapping procedure. The Super Glue will be removed later.

The final step for today was to make the handwheel. It is 1.5″ diameter. The rim is 1/8″ brass and the spokes are 1/16″ brass. I made 4 of these, with each being better than the last. I softened the 1/8th brass before winding it around a 32mm pipe to form the rim. The join in the rim was silver soldered. Then the rim and the hub were drilled using a tilting indexing head on the mill. I soft soldered the spokes on intital handwheels, but the final (and best) examples were glued with Loctite. Loctite allows a few minutes for adjustment of the spoke lengths, whereas there is only one go with the soldering.

It is looking interesting, Yes? And there are 3 spare handwheels. The rest of the reversing mechanism components were made several months ago. Almost ready to install them.

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December 27, 2016

Broken Tap Removal

In a previous post I admitted to breaking a BA7 tap in the Edwards air pump of the Triple Expansion Engine, and being unable to remove it.

The hole being threaded was one of 4 to be used to hold a water pump to the air pump. It was 2.5mm diameter (i.e. pretty tiny)

I tried to grasp with pliers the fragment still protruding but it then broke below the surface.

I tried to break up the embedded tap, using a HSS punch, with partial but inadequate success.

I briefly considered drilling a hole from the other end, and punching in the reverse direction, but that would really have compromised the pump.

So I decided that the three remaining bolts would have to be enough.

A night sleeping on the problem.

Next day, with a fresh determination, I decided to attack the problem again.

I had some used carbide milling cutters 2mm diameter, and I was prepared to sacrifice one or two of them. So I carefully set up the Edwards pump in the milling machine.

triple-expansion-engine-1-23

You can see the three good tapped holes. The carbide milling cutter chomped away at the broken tap, and using gentle pressure, and ignoring the metallic screeches, the tap was broken up and most of the fragments came out. I was prepared to sacrifice the milling bit, but it seems to have survived this insult. The harder metal always wins. It was probably fortunate that the tap was carbon steel and not HSS.

Somewhat surprisingly, the tapped hole was in reasonable condition, and it accepted a BA7 bolt, although I will not be aggressively tightening this one.

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December 20, 2016

Triple Expansion Steam Engine -The water pump

john and audrey - 5.jpg

The triple will not be finished by Xmas. No chance of getting into the workshop while we are looking after 2 grandchildren. So the new aiming completion date is Jan 6, in time to run the triple on steam at the Geelong truck show. If I don’t meet that deadline, the next access to steam will be the end of 2017. I really do not want to wait that long.

So the next component to produce out of a chunk of gunmetal is the water pump.

triple-expansion-engine-1-18

There are two cylinders in the water pump. The gunmetal castings appear to be good quality.

Most of the machining will be done on the mill. But I need a datum surface, and have decided that the attachment plate is the most appropriate.

I do not need the small cylindrical protruberance, but that chunk of gunmetal might be handy for something else (eg as a bushing), so I parted it off and saved it. Lovely parting tool is from Eccentric Engineering.

Then turned a flat surface. On the mill I machined it to a rectangle. Diamond tool is also from Eccentric Engineering.

The two water pump cylinders are bolted to the air pump. BA7. A broken tap is entombed in the air pump forever.

triple-expansion-engine-1-22

When I get back into the workshop I will machine the rest of the pump parts.

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December 17, 2016

MAKING SMALL SPLIT BEARINGS FOR THE TRIPLE EXPANSION STEAM ENGINE

The bearings in the drag link are not split, because they can be slid onto the shaft. But if there are obstructions to sliding, (such as big ends on a crankshaft), the bearings must be split, and assembled when in position on the shaft. The bore in the intact bearings in the photo is 4mm. The split bearings have a 5mm bore. They are all bronze, but the split bearings have been heated then dipped in sulphuric acid so the colour has changed.

The first step in making split bearings is to machine 2 strips of metal, of identical dimensions.

Next the strips are soldered together.

The bearing holes are drilled and reamed exactly to finished size.

The strip of soldered metals is attached to a sacrificial base plate and the outside of the bearings are machined to final size and shape.

Holes are drilled to take the bolts which will eventually hold the halves of the bearings together. (1.6mm holes in this case). The bearings are then heated to melt the solder and separate the halves of the bearings. Sulphuric acid was used to remove the carbonised crap left on the surface of the bronze by the heating torch.

The bosses around the holes was an extra machining step.

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December 15, 2016

Drag

Not what you thought.

Today I made the rest of the drag links for the triple expansion steam engine, and just for fun I made one spare.

I ran out of BA10 nuts. Ordered more. 1.6mm thread, 3mm overall diameter, 200 of them weighs nothing. But if I drop one, that is another 25 cents down the drain, because individually they are invisible.

triple-expansion-engine-1-5

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December 14, 2016

Drag Links for Reversing Mechanism on Triple Expansion Steam Engine

A bit more progress today.

I spent the whole day making these drag links, and I was pretty happy with the result.

Then I realised that I need 6, and I had made only 3. (well there are 3 cylinders you see).

So you know what I will be doing tomorrow….

The drag links are the 3 items with the bearings at the ends, and the connecting rods. Those rods are 1.6mm diameter (1/16″ inch), and the nuts are BA 10

I dropped 2 of the nuts. Gone forever.

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December 13, 2016

The final 20% takes 80% of the time

The weighshaft, supported on its brackets. It will be pinned with taper pins to the shaft. Also finished the reversing lever and reversing arm. The reversing arm has gunmetal bushes. About 2 x 8 hour days in the workshop to make these bits. Just as well it is a fun hobby.

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December 2, 2016

Triple Expansion Steam Engine resumes

Busy at this time of the year.

Making some wooden toys for the grandchildren for Xmas.

Not sure whether these are ducks or chooks. My talented wife brings them to life with colours. When pushed by 1-2 year olds they waddle with an entertaining flap flap walk.

Preparing the surgery building for sale. Removing and storing 34+ years of medical records, moving furniture, arranging repairs and painting etc etc. Feels strange to be no longer a registered medical practitioner, but I know that it was the correct decision to retire. It has taken 2 years to totally burn the bridges by dropping my medical registration, and selling the surgery etc.

Model Engineering Club annual exhibition.

This model quartz crusher at the exhibition was driven by a hit and miss engine.

Another superb engine at our exhibition.

Plus ongoing military history book reading and reviews.

Slashing long grass, to reduce the summer fire risk.

Assembling and installing a kitchen into a rental property.

So it was a treat to get some time in the workshop today. I had previously made the layshaft brackets for the triple expansion steam engine, so I spent a happy few hours setting up an angle jig on the milling machine to drill and tap holes to attach the brackets.

This is the setup. An adjustable angle plate was bolted to the milling table, and the angle was set so the columns were horizontal. The layshaft brackets were Super glued to the columns with the shaft in place after filing to get the brackets quite level. The holes were spotted through, then drilled (1.6mm) and tapped (2mm).

The layshaft bolted in position with M2 nuts and studs. M2 is very similar to BA7, and a lot less expensive, and is stainless steel. Way to go!

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November 20, 2016

Turkish Bombard – the barrel mouth

Except for a name plate I have finshed the bombard. The floral design at 12, 4 and 8 is not as clear as I wished, and the Arabic script at 2, 6 and 10 is even worse. But it is cut in wood, and it is a first effort at such work, and it is not easily seen in a model only 106mm 4.2″ diameter, so I am reasonably satisfied.

Also, this was always a prototype, in wood, and I have not totally dismissed the idea of making it in cast iron or brass. In metal I am sure that the detail work would be a lot finer.

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November 10, 2016

Turkish Bombard. The Barrel Script

Well, I bought a pair of NSK bearings for the Z axis of my CNC mill, and removed the old ones and inserted the new ones. Cost $AUD 200. Plus 2 or 3 half days of dirty heavy work. And the problem persisted!!@!@

OK. Time to get an expert opinion. Here comes the cavalry. Thank goodness for my expert friend Stuart T.

Very puzzling. Even for Stuart. There was some unwanted movement in the Z axis (about 2mm), despite being apparently properly installed. Not a problem with the ballscrew or ballnut. Even Stuart was puzzled.

“have you got any left over bits and pieces? Is it all installed the way it was before?”

To cut the story short, we installed a thicker washer below the locknuts, and it seemed the problem was fixed. Or was it?

Today I did another test run of the bombard mouth Arabic script. Worked fine. OK. Time to finish the bombard.

Here is the finished result, ready for painting. I have used a 20 degree engraving carbide bit with a 0.2mm flat end. There is some loss of fine detail but it is I think, adequate. When it is painted, the filling putty above the pin screws (the white circles) will be invisible. The engraving took a total of about 60 minutes, at 500mm/minute, 15,000 rpm.

The setup. A large angle plate clamped to the table. The work clamped to the angle plate.

The translation of the Arabic script is “Help O God the Sultan Mehmet Khan son of Murad. The work of Munir Ali in the month of Rejeb. In the year 868.”

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November 1, 2016

Turkish Bombard. The Arabic Script.

A little unfinished business on my model bombard is the Arabic script and floral decoration around the barrel mouth.

XIX.164 / 19-00164 Detail of muzzle of a great bronze gun. Turkish, dated 1464 Royal Armouries Museum, Leeds LS10 1LT Transparency tr-1185 Imacon Flextight Precision II

This is what I have managed so far….

It is a practice run in scrap wood.

Some of the detail has disappeared because I used a milling cutter with an end width of 0.5mm. Next time I will add another step using a cutter with a sharp point, and a lot more of the fine detail will appear.

That pattern took a total of 80 minutes to CNC mill, with the feed rate set at 500 mm/min.

Unfortunately my CNC mill developed a problem with the Z axis, probably due to a worn out end bearing. I am hoping that it is not the ball screw nut. Now in the process of removing the bearing. A heavy, awkward, dirty job.

When the mill is working again I will mill the actual bombard model and post some pics.

Computer graphics is not my strong point. To get the CNC mill to cut that pattern I did the following..

Enlarged the photo, outlined the tracery and the script, then traced the outline onto tracing paper. That 550 year old pattern is worn and hard to define in many places. Quite a bit of guess work. Lucky that almost no-one can read ancient Arabic script these days.
Scanned the tracing and loaded the scan into Corel Draw
Used Corel Draw to smooth the curves, and make 3 copies in an array of the floral design
Converted the drawing to bitmap file (bmp)
Used V Carve Pro to convert the bmp file to vectors
Used V Carve Pro to generate the CNC G codes
CNC milled the scrap wood at 16000rpm, using a 3.2mm carbide cutter

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October 30, 2016

After the triple

I am back onto the triple expansion steam engine, after putting it aside for most of 2016. I am guessing that it is about 75% completed. I have been struggling with this project due to poor plans, no instructions and some lack of skill and knowledge.

When I was well into the project, a colleague pointed out that detailed instructions existed in some articles published in 1985 (Model Engineer, Bertinat). I obtained the articles, and subsequent progress has been greatly assisted, but unfortunately some errors had already crept into my work, and these have not been easily or completely rectified.

So now I am back into it. And I would hope to have it finished and working by the end of the year. Watch for pictures when there is something to show.

I am already thinking about what will follow the triple. Maybe a Harrison 1 clock? (of “Longitude” fame.) Looking for some plans.

Or maybe some more artillery? How about a working model trebuchet? Now that does have some appeal. There are some plans on the Net, but they look over simplistic. I am thinking of a more historically accurate model. The following picture is from an old French encyclopaedia. But I might have to abandon my preferred scale of 1:10 because the original was about 12 meters long. But on the other hand……

It does have some interesting features. The ratcheted windlass, the travelling pulley, the trigger mechanism (“pulling the pin”), and the projectile release mechanism (trying to avoid the projectile going up vertically).

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Image | October 26, 2016

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October 12, 2016

More Scale Stuff

There is the 1464 Turkish bombard (black), 17 tons, 307kg granite ball; the 1779 long naval gun off USS Constitution or HMS Victory 24lb balls; and a 32lb carronade. All 1:10 scale. Interesting to see them together on my kitchen table?

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October 7, 2016

Model Ottoman Bombard – Painting

I would have preferred that the title of this blog was “Finishing the Ottoman Bombard”, but I am still waiting for the vectors of the barrel mouth decorations and Arabic (?) writing, and the touch hole.

But I have at least painted the bombard, and the pictures follow. You will notice that I have not attempted to reproduce the bronze or copper colours of the orginal in Fort Nelson. Partly because I doubted my ability to make painting such variegated patterns realistic, and partly because the cannon would not have looked like that in its heyday of 1464. It would probably have been either black, like most SBML cannons (smooth bore muzzle loading), or possibly gaudy golds and reds and blues like other medieval items. So I painted it black. I like it. If I get evidence that it should be more colourful I can change it later.

First coat – Primer. Hmmm… interesting colour.

Next coat – matt black brushed on, to fill the hairline wood cracks. Incidentally, the (dirty) parquetry floor is also made from the red gum house stumps from which the cannon is made.

final two coats – matt black, from a spray can.

So there it is, finished except for the barrel mouth engraving, and the touch hole. Now what to do with it… SWMBO says it might be useful as an umbrella stand.

The breech. 25mm diameter explosion chamber. 1:10 scale

The barrel, 63mm bore.

Assembled. The model is 520mm long.

It does need some decoration

turkish-bombard-plan

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October 6, 2016

Ottoman Bombard Photo to Vector

Bombard mouth.jpg

This is the low res photo from Fort Nelson. High res photo on its way.

In the meantime, I have contracted with a US firm to convert the picture to vectors. More $US. ($US50 to be exact).

I am not sure that this is going to work. But I will report to you.

I do wonder what that the Arabic/Turkish writing means. Does anyone know? I am pretty sure that it is not complimentary to Christians/Westerners/Non Muslims. Maybe it is just an instruction not to look before the touch hole is touched. Or “do not stand here”.

PS. Note added 17 Oct 2016. The translation is “Help O God the Sultan Mehmet Khan son of Murad. The work of Munir Ali in the month of Rejeb. In the year 868.”

868 = 1464 ce.

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October 3, 2016

TURKISH BOMBARD- HELP!

Does anyone have a decent photograph of the writing on the muzzle?

I have repeatedly hunted through every picture which I can find on the net, but they are either taken at an angle, or too poor quality to be useable.

Does anyone have a photograph which I could beg buy or borrow?

I also need a photo of the touch hole.

I have contacted the Fort Nelson Armoury Museum, but not too surprisingly there was no response.

Is there someone in the Portsmouth UK area who could pop in and take some pics for me?

POSTSCRIPT: October 5. I have had 2 excellent and positive responses to my appeal.

First, reader Richard sent me a connection to a Turkish Dr/Professor, who has made a 1:25 model of the bombard using 3D printing. (at least that is how I think he has done it. My Turkish is non existent). I am following this lead.

Secondly I have had a response from Fort Nelson Armoury, with a good photo of the barrel mouth, and a high res photo on the way, after payment of a significant, but not unreasonable fee. Isn’t the Internet wonderful!!

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October 1, 2016

TURKISH BOMBARD – the real thing

I have found this video to be particularly useful in my modelling of the Ottoman bombard. The subject of this video is the gun that the Turkish sultan gifted to Queen Victoria when the Brits and the Turks were allies. It might be one of the guns which fired on the British fleet in 1807, when it (the gun) was 343 years old!

Notice the colour. It is aged bronze. I am thinking about how to reproduce that colour on my model.

Length of the assembled gun 5.2m (17′)

Bore 635mm

Breech weight 8942kg

Barrel weight 8128kg

Average weight of shot 307kg

the model is at a scale of 1:10. photos soon. being painted.

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September 28, 2016

Modelling A Turkish Bombard- The Pins

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There are 16 pins at each end of each section of the cannon.

These were certainly used as leverage points, for very strong men with large levers to rotate the 8-9 tonne segments against each other to engage and tighten the screw.

I cannot see how the pins would have been cast with the breech and barrel. For my model I decided to make separate pins and fit them into the gap between the big rings, then insert a grub screw through both rings and the pin. The holes are then filled.

I wonder if a similar method was used in 1464. I would love to have a close look at the original cannon to figure this out. From the photographs, I can see no evidence of later insertion of pins, but neither can I see how it would have been done any other way.

Drilling the holes for the grub screws

In order to continue with red gum, I made my own pins. This is the setup. The blank is held approximately centre in a 4 jaw….

…and the pins are turned, centre drilled, drilled, cut to length, and tapped M4. 64 altogether.

The M4 x 25mm grubscrew is screwed into the pin. The wood join is super glued. Also, I am attempting to patch the worst of the thread tearouts.

Using a battery screwdriver to insert the grub screws. The pins protrude above the ring surface for a reason..

Sanding the pins flush with the rings. Check the photo of the original 1464 model. There is also some wood filler in other splits. Not surprising after holding up a house for 70 years.

The holes are now filled with wood filler, and will be sanded flush. They should be invisible after painting.

Next the painting, the stands, and some cannon balls. How to reproduce that aged copper colour…

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September 23, 2016

Modelling a Turkish Bombard -4 Decoration

The decoration around the barrel is formed by a repeating pattern, which when milled, very cleverly forms 2 identical patterns. One is excavated and one is the original barrel surface. You will see what I mean if you look at the pictures in the earlier blog, and the video below.

It took me an evening of experimenting on the computer to work out the system and draw it.

bombard-pattern3

Then I measured the diameters of the 2 gun components, calculated the circumference, (OK it is not rocket science. 3.142 times diameter), then working out the number of identical shapes which would fit around the 2 different diameters, at the same size and spacing. Amazingly, it took 18 shapes to fit almost exactly around the barrel, and 16 of identical size almost exactly around the breech. the angular spacing was 20 degrees and 22.5 degrees.

Then the shape was imported into V-Carve Pro, and G codes were generated.

My CNC mill does not have a 4th axis, so I used a dividing head to move the workpiece at the precise angles. See the setup in the video. That meant that the pattern was engraved into 16 and 18 flat surfaces, rather than a continuous cylinder as on the original.

It worked very well. There were minor compromises due to the shapes being milled with a fine end mill but when you look at the pics I hope that you will agree that it is effective.

I calculated that the milling had to be at a maximum depth of 2mm in order to cope with the curvature, but if I do it again, I would reduce the depth by 25%.

The first part of the video is a shot of CNC drilling. Then the CNC routing of the repeating patterns. Each angular setting of the pattern took 4 minutes to complete. 136 minutes altogether. In reality, it took a whole day, most of which was spent doing the setups.

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September 19, 2016

Bombard Model-3 turning the barrel

Another session or two, and this project is complete.

Now how do I make a cannon ball 62-63 mm diameter? In wood will be ok? Does not have to be granite. I could make a mould and cast it in aluminium or lead, but stone would be authentic….. thinking.

ps. Re cannon balls. I will cast them, in cement! Now, how to make a mould.

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September 19, 2016

Bombard Model -2. Big Thread

The breech and the barrel are joined with a very large thread. On my 1:10 scale model it is 60mm diameter, and has a pitch of 6 mm. These dimensions are measured off Internet photos of the original bombard, so they might not be faithfully accurate to the original bombard. If anyone has accurate plans of the bombard I would be very interested to hear from them.

I experimented with various spindle speeds, feed rates, depth of cut, and finally decided that red gum wood is not the ideal material to be cutting a thread with sharp points. However, at 200rpm, and taking 50 cuts to reach the full depth, and using a very sharp tool, the end result was OK. I will fill the tearouts.

In order to make a functional join in the wooden cannon, I truncated the apex of the thread. In the gunmetal version I will attempt a more faithful to the original, sharp look.

For some reason, the wood held together better during the internal thread cutting than the external.

The male thread was cut on my newly CNC converted lathe, between centres, but the fixed steady on that lathe was just too small to hold the barrel, so the internal thread was cut on my bigger Chinese lathe.

Next I will bore the barrel to 63mm, then turn the exterior of the barrel.

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September 17, 2016

Bombard Model. Turning the Breech

So if you watched the video, you can see that I have a problem with the big thread between the breech and the barrel, at least in the wooden prototype. It might work better in brass or gunmetal.

The thread has a pitch of 6mm and a diameter of 60mm. It is big.

My plan at this time, is to make a brass male threaded section, and glue or screw it into the breech. Then to make a steel tap using the same G code, and cut a thread into the wood of the barrel. (p.s. note 30 Sep… I continued to experiment with feeds, speeds, and cutter shapes in the wood. The final result was OK so I did not make metal threads. That will have to wait until I do this project entirely in gunmetal or brass… maybe never)

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September 13, 2016

Turkish Bombard 1:10 scale

Just for fun I will use my newly converted CNC lathe to make a 1:10 bombard. The original was cast in 1464 and was thought to be a close copy of the bombards which Mehmet 2 (“the conqueror”) used to breach the walls of Constantinople in 1453. There are several of these bombards still in existence, including one in UK, which was given to Queen Victoria by the then Turkish Sultan.

These bombards were last used, against the British, in 1807, when a British warship was holed with substantial loss of life. Pretty amazing for a 340 year old weapon.

5.2 meters long, 1.060 meter diameter. 16.8 tonnes.

The large thread connected the halves. Easier transportation, and casting.

Is this Turkish or Arabic?

Granite balls are 630mm diameter.

A reconstruction of the walls of Constantinople, with moat. Almost 1000 years old in 1453

And as they are today. Massive. High.

29962555-Huge-siege-the-final-assault-and-fall-of-Constantinople.jpg

Huge siege cannon used in the final assault and fall of Constantinople in 1453. Diorama in Askeri Museum, Istanbul, Turkey. The bombards were probably dug in, to manage the massive recoil, and concentrate the aim at a particular wall section. There is a wooden structure built around the cannon in the background of this modern picture. As far as I know there are no surviving wooden structures like this. Nor have I come across any old pictures, but if anyone knows of any I would be very interested. The bombards took about 3 hours to cool, cleanout and reload.

My model will be about 520mm long. I would like to make it from bronze, or gunmetal as in the original. Any mistakes will be costly.

So I have decided to make a prototype in wood. That will test my drawing, the machining procedure, and the final appearance. Not to mention how the CNC lathe will handle the task.

I will use a very dense, tight grained Australian hardwood (red gum). The wood was salvaged when my house stumps were replaced with concrete. Some was used to make parquetry, and the rest was put aside for possible future use. Such as this.

About to cut off the below ground section of a 70 year old house stump.

A 5hp metal lathe with a tungsten bit chomps through the hard dry wood.

I turned 6 lengths before I found 2 that were satisfactory. The rest had sap holes or splits.

I have used Ezilathe to generate the G codes.

to be continued….

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September 6, 2016

CNC Lathe Conversion- final

Before I am hung, drawn and quartered, for operating a lathe without guards, here is the proof that I have been sensible.

Guard over the X axis pulleys. I like to watch the wheels going round and round, hence the transparent top. Also note the cover over the exposed ball screw.

Cover over the Z axis pulleys and belt, again transparent. If I wore a watch it would be transparent.

I also installed an ER40 collet chuck. I will be using this for all work with diameters under 26mm.

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September 6, 2016

A Matter of Scale

Before I get onto a brief reflection about scale, the photo below shows 2 cannon barrels.

The big one was what impelled me to converting a manual lathe into a CNC lathe. That time consuming, costly, and ultimately very satisfying project, started because the CNC lathe which I used to turn the big barrel could only handle the job by doing it in two stages…. doing the breech first then the muzzle. That was due to the big barrel being too long for the lathe, at 300mm (12″).

The small barrel was a test for the CNC converted lathe just finished, being the first complicated shape which I have made. To save on material, I made it at exactly half the scale of the big one, ie 150mm long (6″).

Comparing the two barrels reminded me, that if an object is twice as big as another, in all 3 dimensions (height, width, depth), it is 8 times as heavy. And any projectile, and weight of black powder, would also be 8 times the weight. But the wall thickness of the explosion chamber is only TWICE as thick.

My point is, that if scale is maintained, the smaller the cannon, steam engine, boiler, whatever….. the less likely it is to explode.

Not that these cannons will ever be fired. Just hypothetically.

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September 4, 2016

CNC Lathe Conversion – 17

First Test Run

After some test runs without tool or material, I performed some measurements.

500mm movements along the Z axis were reproduced multiple times with a deviation of 0.00mm! (the Z axis has a ground ball screw)

100mm movements along the X axis deviated 0.02mm. (the X axis has a rolled ball screw).

I was delighted to note that the lathe is extremely quiet and smooth. The only noise is some belt slap from the very old belts, and from the stepper motors.

The video below was taken from my iphone, while I was operating the lathe controls, so please excuse the erratic movements.

The steel is 27mm diameter. 750rpm, 50mm/min feeds.

And the guards will be made next step, without fail.

The G code was generated using Mach3 for these very simple shapes. For more complex items I use Ezilathe.

The lathe is 600mm between centres. 38mm spindle bore. Swing about 300mm.

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August 31, 2016

Steam Engine Oilers

Knowing that I have an interest in CNC machining, Tom, from the Vintage Machinery Club in Geelong asked me to make a pair of oilers for a very old Wedlake and Dendy steam engine. The engine is a large (to me anyway) stationary engine, which is run on steam several times each year. The oilers for the cross slides were missing.

We searched the Internet for pictures of W&D steam engines, but could find no pictures or diagrams of the oilers. So Tom sketched a design, and I drew a CAD diagram. The dimensions were finally determined by the materials which I had available… some 1.5″ brass rod and some 1.5″ copper tube.

This is the almost finished product.

Just needs 1/4″ BSPT fittings and and oil wick tube so they can be fitted to the engine.

The copper tube silver soldered to the brass cylinders (top), the brass blanks for the lids (bottom) and the mandrel to hold the assembly (bottom centre) during CNC turning and drilling.

The mandrel to hold the body (left) and the mandrel for the lid (right). The cap screw head and hole in the mandrel have a 2 degree taper. The slits were cut with a 1mm thick friction blade.

Rough turning the base.

Turning the lid. The mandrel is held in an ER32 collet chuck

Engraving the lid. Using a mister for cooling and lubrication. 16000rpm, 200mm/min, 90 degree TC engraving cutter.

The oilers work by wicking the oil from the reservoir into a tube which drains through the base onto the engine slide. When the wick tubes are fitted the oilers can be fitted to the engine.

The 1865 Wedlake and Dendy

1865

My lathe is a Boxford TCL125, using Mach3. The G code is generated using Ezilathe.

Below is a link to an oil cup from “USS Monitor”, of American civil war fame. One of the first ironclads, powered only by steam.

http://www.marinersmuseum.org/blog/2010/04/one-oil-cup-down/

(ps. The lathe which I was converting to CNC was the subject of previous posts and is now working, but needs some guards fitted and a bit of fine tuning.)

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August 29, 2016

OK, so guess the purpose

A pair of sheet metal pliers, to which I welded a steel tab. Why?

For the answer click on the link.

For some reason the auto link is not working. You will have to type the link manually.

Later update… I dont get this. Even the manually typed link to the explanation does not appear.

OK. The explanation is that these sheet metal pliers have been converted into canvas stretching pliers for my daughter who likes to make her own canvases for oil painting. Youtube sucks sometimes.

Try searching “Thomas Baker’s canvas stretching tutorial” to see how the pliers are used.

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August 13, 2016

MORE ANCIENT GREEK TECHNOLOGY, THE ANTIKYTHERA MECHANISM

This mechanism was discovered in 1901, in a Roman era shipwreck, off the Greek island of Antikythera, which is a bit north of Crete.

It has been dated to between 100BCE and 205BCE, with the older date considered the best estimate. ie, about 2200 years old. Experts believe that its makers were Greek.

It is currently housed in the Greek National Archeological Museum in Athens.

Not much at first glance, but when it was examined with modern scanning and X ray techniques…

Look it up on Wikipedia..

https://en.wikipedia.org/wiki/Antikythera_mechanism

According to the Wikipedia entry the gear teeth are too irregular to have been machine cut,

but watch the computer reconstruction. Could you make this machine without a lathe and gear cutters?

How much more technology did the ancients have that has not survived the ravages of time? A lathe for example.

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August 12, 2016

ANCIENT GREEK MACHINING

I recently had a light globe switched on in my brain.

I was holidaying in Athens (the one in Greece), and was gobsmacked by the huge, fabulous collection of statues, mosaics, ceramics, gold jewellery and masks, bronze and iron weapons in the National Archeological Museum. I took many photos, and might post some in later blogs.

Three items sent shivers down my spine.

The gold death mask of Agamemnon (probably not Agamemnon’s but that is another story).
The Antikythera machine. More about that in a future post.
A gynaecological speculum.

There was a display with many surgical instruments. These have been found at various archeological digs in Greece, and while not precisely dated (at least not labelled) they are mostly from 500-200 BCE.

My eye was immediately drawn to an instrument which looked very familiar. I was a gynaecologist in my previous life, and this could have come from my instruments. (except that the dark bronze surface might not have been acceptable to patients).

Not a great photo, through a glass cover, and ISO cranked up to several thousand.

The instrument is labelled a vaginal dilator, but I am quite certain that it is a vaginal speculum. A speculum is used to inspect the vaginal walls and uterine cervix. (That might be too much information my metal working/ engine making/ machinery minded readers. If so, too bad.)

It is said to be made of bronze. The Ancient Greeks were highly skilled at metal casting, as evidenced by the many complex and beautiful bronze statues and weapons and implements on display.

It interested me for several reasons. Bear in mind that not many archeology museum visitors are gynaecologists who know about making threads in metal.

It looks quite functional, and if cleaned up, given a shiny surface and sterilized it could be used today.

The threaded section is very regular and smooth. I would loved to have taken some measurements of the thread with a micrometer, but had to be content with a prolonged inspection through the glass case. The thread appears to me to be so regular, that it could not have been hand filed. It must have been machine made. I have seen hand made threads on medieval machines, and they are crude compared with this one.

Either this is not an ancient Greek instrument but a more modern instrument accidentally included in the display (pretty unlikely, considering the professionalism of the people involved). (ps. If you Google Pompeii speculum, you will see that similar instruments have been unearthed at Pompeii… buried since 79ce.)

Or….. the ancient Greeks had screw cutting lathes.

Ridiculous you say?

Wait until my next post about the Antikythera machine. If if you just cannot wait, look it up. It is mind blowing.

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July 20, 2016

CNC Lathe conversion -16

The wiring of the lathe is complete. (Except for limit switches. They can be added at any time).

Mach 3 is configured. The wireless hand control is installed and working. Ezilathe installed and waiting for input.

Some covers to be made.

Hook ups in progress. That’s the faulty VSD on top of the electronics enclosure. The CNC engineer lost his hair trying to figure out the problem.

Still some testing and fine tuning required.

But nothing much will happen in the workshop for the next 3 weeks.

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July 17, 2016

CNC lathe conversion -15

Another couple of advances in the conversion. Today I installed the lead screw cover and the cable protector to the cross slide stepper motor.

The cable protector was easy and straightforward. It flexes in one direction only, and is fixed at the ends after the cable is threaded through it. The length is adjusted by adding or removing links. It was placed so that coolant liquid will drain out of it, and to minimise the accumulation of swarf. The cables themselves have a thick covering and are well protected. The link protector will not kink, further protecting the cable.

It was cheap. About $AUD20 for 2 meters, posted from China. I used about 1.1m.

Showing the stepper motor cable protector, and the lead screw protector (one half of it. The other half is on the other side of the carriage.)

The lead screw protector was another story. It is a spring steel coil, about 50mm wide, and as it is compressed the coils fit inside each other. I made a big mistake in allowing it to spring open before I had installed it (there were no instructions). It immediately opened to a length of over a meter, in coils about 50-60mm diameter. No big deal, I thought. I will just compress it back to its original configuration. Big mistake.

It was what I imagine coiling a live, oily, biting, boa constrictor would be like. (OK, boas constrict rather than bite. How about an anaconda, or a big eel.)

I fought it for about an hour. And eventually succeeded. Minus a few bits of my skin.

So I did not allow the protectors to expand again until after I had them on the lead screw.

This is what they look like. Pretty cool IMO. They just expanded into position when I removed the restraining clips.

The lead screw stepper motor and protector. The Estop box above will get some ends to exclude swarf.

It was not cheap. The best price that I could find was from South Korea. $AUD200 inc postage. But it is excellent Japanese quality.

The wiring is happening, but the variable speed drive seems to be dead. It has been sitting unused on a shelf for 2 years, so no point asking about warranty. Took it apart to check for broken wires, fuses, burnt out components etc, but nothing visible. Will order another one. About $AUD200. An unexpected expense.

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July 11, 2016

CNC lathe conversion -14

These lathe CNC conversion posts are probably becoming a bit tiresome, but just in case there is someone out there who is interested, I will continue until the job is finished.

The latest was to make and install a spindle speed (and position – thanks David M) sensor. It consists of a disk with a slot cut in the periphery, attached to the main spindle. And an opto-electronic sensor which is connected to its own electronic board, thence to the breakout board and VSD.

The disc with the slot at 8:30 and the sensor at 9:00. I must have chosen the wrong cutter or turning speed for that disc aluminium… looks a bit rough. (note added 13/7 Stuart T says that I should have used coolant-lubricant).

View from above. Any clearer? That gear is now superfluous except as a spacer.

So there is one electronic impulse per spindle revolution. That is enough to measure the RPM’s. Essential for cutting threads.

The beauty of this system is that there is no gear selection or changing, and ANY thread pitch can be selected… metric, imperial, BA etc… any odd ball thread that your heart desires.

cnc lathe - 2

The HTD (high torque drive, I am informed by many readers) pulleys and belts and taper lock fittings. Unfortunately I could not find a taper lock to fit the small pulleys, so when it is all finally, definitely, absolutely, correctly, positioned, I will Loctite them in position. Protective covers yet to be made. I quite like to see the mechanicals in action, so I am intending to make the covers from clear polycarbonate.(Lexan) .

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July 9, 2016

CNC Lathe conversion -13

Adjusting the lead screw.

The 48 tooth HTD pulley has been installed using a taper lock.

Then some time was spent adjusting the parallelism of the lead screw. That requires quite a few movements of the carriage along the 600mm thread. Each 360 degree turn of the lead screw advances the carriage 6mm, so you can understand that I became a bit impatient with all of the repetitive hand actions to move the carriage from one end to the other.

So this was a solution to that issue. That HTD belt is the one that was too long, so I was happy to find a use for it. The variable speed battery drill shot the carriage end to end in a couple of seconds.

All is now adjusted parallel.

A few more little installation issues, then for the wiring.

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July 7, 2016

CNC Lathe conversion -12

Today I fitted the lead screw.

No big deal, I sense that you are thinking. After all, the ends are machined, the bearings fitted, and all waits in readiness.

True, but there is a strict sequence of events. And since it has been 3 or more weeks since it has been together, I had to rediscover the sequence, by trial and error. And each bit of the fitting is very heavy, very delicate, very tricky. So it took me several hours to get to the final photo in this blog.

But first a view of the inside of the newly machined apron.

The lead screw fitted. The cross slide screw is also fitted. Note the red E Stop panic button fitted to the left. Next job is to fit a support bearing at the right hand end of the screw. Then to check and adjust parallelism of the screws. A rough check showed that they are within 0.25mm

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July 6, 2016

CNC Lathe conversion -11. Ball screw machining.

Hooray!

Today I collected the lead screw after the ends were machined by Statewide Linear Bearings.

I decided to drive the 100km each way to pick it up, in preference to using a courier. I wanted to ensure that all of the small bits were there, and also just to make sure it was handled properly. Mostly freeway, listening to Dan Carlin on the Persian-Greek wars, so it was a pleasant way to have 3-4 hours to myself. (If you do not know about Dan Carlin, Google him and download an episode. If history at school had been like this, we would all be history addicts.)

This is the lead screw, ends machined, and support bearings fitted. 1100mm long. 28mm dia

All good, except that the nut was back to front. That nut is pre-tensioned, which means that the 2 halves are separated by a precisely machined washer. I was nervous about removing it and replacing it the correct way around. However I had previously asked the ball screw expert about that aspect, so armed with the technique I made up a sleeve of the correct size, removed the nut and replaced it. No balls fell out. So all good! The above picture shows the nut in its correct position.

The nut. Looks expensive? Is expensive. And beautiful.

The machined driven end. $AUD250 machining there. But it is perfectly done.

And with the support bearing installed. A pulley for the HTD belt goes on the distal bit of shaft.

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Image | July 5, 2016

The CNC lathe has 3 belts. There is a V belt from the 3 phase motor to the main lathe spindle. Although I changed the motor and the pulleys, the old belt fitted, which was good. No hassle. But the stepper motors driving the lead screw and cross slide screw, and their pulleys were all […]

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July 4, 2016

CNC Lathe conversion – 9

The CNC lathe conversion has been happening, despite no posts on the blog.

I have mounted the electronics enclosure, and mounted the various components inside. No wiring yet.

This stainless steel tool box is the electronics enclosure. It fits the space quite nicely, and is adequately big. The back gear cover to the right will be retained, although the back gears have been discarded. The main switch and emergency stop will be mounted somewhere on this cover.

The Variable speed drive (VSD) sits on top. That will control the spindle speed. The transformers, stepper motor drives, and Breakout board (the heart of the system) are positioned inside. Plus cooling fan and filters. Ready for wiring.

Drilling the apron to attach the cross slide ball screw bearing. One chance only at this one, so the setting up took a couple of hours. The apron is clamped to a large angle bracket on the milling table. M6 threading followed.

The end result. The bearing as attached to the apron and the ball screw is in place. I machined the end of this ball screw to fit the bearing, cut a thread (M10x1), and machined the end to accept the pulley. All good. There is 0.25mm adjustment available if required, but it all seems pretty correct. The bearing sits on a carefully machined block which is 7.85mm thick. Still waiting the lead screw machining.(!!)

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	John on Byrnes Style Saw Bench
	Anonymous on Byrnes Style Saw Bench
	John on Bellerophon -3
	John on Bellerophon -3
	oldimperial on Bellerophon -3

	John on Byrnes Style Saw Bench
	Anonymous on Byrnes Style Saw Bench
	John on Bellerophon -3
	John on Bellerophon -3
	oldimperial on Bellerophon -3

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Image | October 26, 2016

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