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.

Southworth Steam Pump- first parts

A couple of days in the workshop, and the large castings are almost fully machined.  Straightforward machining.   Made a couple of mistakes, but none fatal.  Changing BA fasteners to metric.

P1032887.JPG

The steam cylinders block in the mill vise.   Almost complete water cylinders block sitting behind for the photo.

P1032888.JPG

Steam cylinders on right, water cylinders on left.  The temporary steel pins are to ensure accurate alignment of the 2 blocks.   Water and steam passages come later. 

This is the first model machining which I have done since April.  It should be second nature, but I admit to a bit of hesitation, nervousness, initially.  Especially starting on an irregular, slightly complicated shape like these.   But it is all coming back now.  And I am really enjoying it.

Steam Powered Water Feed Pump

My CNC mill is now mostly functioning, although several functions are yet to be connected.  The main spindle and XY&Z axes are working, and responding appropriately to Mach3 commands from the laptop computer.  It has taken longer than anticipated so far, mainly due to difficulty in understanding manuals supplied from Asia.   Axis limit and homing switches, oil pump, coolant pump, work light, and cooling fans still to be connected.

So there has been little of general interest coming out of my workshop.  Hence no posts on this site.  Not that I have been idle.

I disassembled the top slide on the Colchester lathe to discover the cause for excessive back-lash.  It was a worn acme thread bronze nut.   No luck yet in finding a new nut for this 45 year old lathe.   I will have to make one.  Meanwhile, I used a quick and dirty trick to reduce the back-lash which I will detail soon.

IMG_8156.JPG

The top-slide acme screw and bronze nut which needs replacing.

I also cleaned and freed up a 3 jaw 10″ chuck which I bought on Ebay.  It was frozen solid, so I soaked it in kerosene bath for a few months.  Actually, I forgot all about it while it was in the kerosene, and accidentally rediscovered it.   This time, after using an impact screwdriver, I was able to open it up and expose the gears and get them moving.  Might be worth a photo also.

IMG_8161.JPG

The 240mm diameter chuck.  I was tempted to buy by the removable, reversible  jaws.  Thinking that I could make some soft jaws.   Trouble is that it is an industrial production line chuck with very little movement.   But it is nice and tight.  Still deciding.  At least I can wind the jaws in and out a bit now.

And I finally got around to installing piston rings in the triple expansion steam engine.  Used Viton O-rings.  Not a difficult task, and it should not be difficult to replace them from time to time in future.   Will be interesting to see if the engine performance improves.

Now to get onto my next project.  I have plans and bronze castings for a Southworth design water pump, for replenishing the vertical boiler water while it is in use.  It was a surprise to me, just how much water is consumed by a boiler which is powering a model steam engine.  To date I have used a hand pump, but having seen a steam powered pump in action, I have decided to make one.

The steam is supplied from the boiler which is being replenished.  The pump has to use steam at boiler steam pressure, to force water into the boiler.  So the pump has to raise the pressure of the feed water above the pressure of the steam which is powering the pump.   The clever pump design uses large steam driven pistons to drive smaller water pump pistons.

IMG_6664

Larger steam pistons top right 5/8″ dia,  water pistons bottom left 3/8″ dia.

Here is a video of a Southworth pump in action.  It was made by Stuart Tankard.  Here it is running on compressed air, but I have seen it working similarly on steam.  I will be making one of the same design, hopefully approaching this level of finish.

 

 

A build of larger version of the pump was described by J. Bertinat in  a series of articles “Model Engineer” in 1993 (first article 18 June 1993).

Screen Shot 2019-08-20 at 9.39.27 am.png

Southworth castings.jpg

The unmachined castings.  Lumps of rough bronze.   And the plans.

water cyls casting.jpg

One of the castings after preliminary machining to establish some faces.  The “water cylinders” block.   Part no. 6

P1032886.JPG

Good quality castings.

 

 

CNC Mill Upgrade -8

Fitted the new VSD Friday.  Ordered Tues pm.  Arrived Thurs am.  Impressive.

$AUD315, inc shipping.   Job cost is mounting.  Still within reasonable limits.

P1032876

The old VSD, top right.  The axis controllers (top left) had not been wired when this photo was taken.

IMG_8151.JPG

The new VSD (variable speed drive) 4kw.  Fitted neatly with some new mounting holes, without any drama.  The rats nest looks less daunting every day.

Now, except for the main spindle motor, there are no more original major electrical components.  All have been updated and replaced, along with the cables.

Yet to be wired are the VSD, coolant pump, oil feed pump, limit switches, homing switches, and the Gecko driver and 48v power supply for the rotary table.   But the mill is useable now.   Video coming up soon.

 

CNC Mill Upgrade – 7.

2 steps forward, 1 step back.   That’s what this project is experiencing.

The axis servo motors, their controllers and connections to power, breakout boards, and computer connections are complete, and all working.

An old laptop has found a use.  Installed Mach3, Vectric V-Carve Pro.   And the connections to the Smooth Stepper board.  Windows 10.   Deleted all non CNC related programs to gain space on the hard drive.

A problem with the main spindle.  It is essentially unchanged from the original.  Same motor (4kw/5hp 3 phase), same VSD, and same 3 phase power which is supplied through a phase changer, because the property has only 2 phases supplied.  When powered up, it worked, but the RPM’s could not be altered from a very slow rate.  The controlling voltage from the breakout board was not changing despite changing the inputs.  ? due to a problem with the settings, or a faulty BOB.  Didn’t seem serious.

So I was a bit surprised when later I switched on the mill, intending to change some settings, to hear 2 significant pops, and to smell that disgusting burnt electrical component smell, with smoke coming from the electrical enclosure.

Quickly shut everything down, and waited for the cavalry to arrive.

Stuart found that a 24v power supply had failed.  No big deal.  Not an expensive component.  Maybe got a short circuit from a bit of swarf?   But further inspection revealed that the VSD had also failed.  A capacitor and diode burnt out.  ? caused by a surge from the failing power supply? Repairable, but I decided to buy a new VSD.  The failed VSD is probably as old as the mill (24 years), so it had a pretty good run.  If the old VSD is repairable, it will serve as a spare.

Meanwhile, as a consequence, the main spindle is not working.  I have a list of jobs that I want to get into, particularly the steam pump for the vertical boiler.   So I will reattach the high speed spindle and use that.  It is 2.2kw, but uses high revs to develop power, so I will be limited to small end mills and drills, until the new components (VSD and power supply) arrive.  The high speed spindle is single phase, and the speed control is manually selected.   Not quite as convenient but useable for the time being.

While Stuart has his head buried in the electrical enclosure, I have been his gopher and TA.  But also fitting in a couple of other jobs which have been on the “to do” list for ages.  Like clearing out rubbish from the workshop, tidying up etc.

One task which has been vexing me, was to remove a sheet of flooring board which was under the Colchester lathe.  The sheet was originally placed under the lathe to protect the vinyl floor covering, but it was not a good decision.  As the flooring board became wet with cutting oil and coolant, it would swell and shrink, and I was aware that the lathe levels and settings were changing.  So I decided to remove the sheet of flooring, and let the lathe feet sit directly on steel pads on the vinyl/concrete floor.

But how to remove the sheet of flooring from underneath the almost 1 ton lathe?  The lathe was originally placed into its rather tight position with a forklift, which is no longer available.  The wooden sheet was the same size as the base of the lathe.

So I made these…

img_8146.jpg

The bolt adjusts the height of the jack.

IMG_8142.JPG

From a piece of scrap I-beam.

I used a crow bar to raise the corners of the lathe enough to place the jacks into position.  A bit of trial and error to get the heights correct.    When the lathe was about 25mm clear of the flooring, I pulled the sheet out.  Then used the crowbar to remove the jacks, and lower the lathe onto its base plates.

I will reset the lathe’s screw feet in the next day or 2, using a precision level and test cuts.  There was an excellent YouTube video by “This Old Tony” on the subject recently.

 

CNC Mill Upgrade – 6. Where to put the computer?

Not much more to report today, but I have decided how to position the computer.

Not easy, because the computer needs to be protected from flying swarf and coolant spray from the CNC mill and the manual mill which is immediately adjacent.    And I want the computer to be close to the machine.  The CNC mill is NOT in an enclosure.

So this is what I have decided….

IMG_8128.JPG

The laptop is just low enough to reach while standing.   The E stop and other buttons are underneath.

And if the swarf is really flying, I can turn the PC away…

IMG_8129.JPG

Might need some adjustments.  The laptop is an old Dell ATG.   Said to be resistant to fluids and relatively resistant to shock/vibration etc.   Military specs.   I might add some side protection and perhaps a roof.

 

 

CNC Mill Upgrade -5

I have been putting quite a few hours into the upgrade, but not much to show photographically.

Finally got the new servo motors installed.  Replaced the X axis belt.  The most difficult servo to access was the Y axis, and of course that was the only one where the alignment of the timing belt was out.   Finally sorted by using a fibre optic camera to see why the belt was climbing onto the flange of the pulley.  The pulley was 1.2mm too far onto its shaft.  I know that, because I solved the problem by inserting washers under the motor mounts.  1mm washers did not work, nor did 1.5mm washers.  But 1.2mm washes did work perfectly.

Today Stuart arrived and removed more of the old wiring.

P1032880.JPG

Stuart, doing another CNC upgrade wiring.

P1032881.JPG

The old 7k computer has been removed, leaving some buttons.  I might be able to use those. The computer enclosure might disappear too.  Not decided yet.

P1032882.JPG

The old CNC mill has lost some weight.  Those cartons are full of old parts.  Note that the floor has been swept.  Stuart was concerned that we might be infested with snakes, but it is winter here, so we should OK until the weather warms up.

P1032883.JPG

The rats nest is disappearing.

CNC Mill Upgrade -4

I removed the old XY & Z axis servo motors from the mill.  Each one weighs about 15kg (33lb).

IMG_8119.JPG

The old servo motors.  The X and Z were working fine.  The Y was faulty, but I do not know whether the fault was in the motor, the encoder, the controller, or the connecting wires.  I will put them on Ebay as 2 working, one for parts.

Then I removed the belt drive pulley off each motor.  There was a grub screw, which would not budge.  Assuming that it had been Loctited, I applied some heat, judiciously.  The grub screw came out, but the pulley would not budge, so a little more heat, and a gear puller.   Two of the gears came off, but one still would not budge.

I asked for advice, and I was loaned a different type of gear puller. (thanks Rudi).  This time, some movement of the gear on the shaft was noted, and eventually the last motor gave up its gear.

img_8122.jpg

This one worked.

The shaft of the old motors was 16mm diameter.  The new motors had 19mm shafts.  So I spent some time on the lathe boring out the gears to fit the shafts of the new motors.  The keyways of the old motors were 5x5mm, and the new ones were 6x6mm.  So, I borrowed a 6mm broach (thanks Stuart), and enlarged the keyways in the rebored gears to 6mm width.   The new keyways needed a lower profile, so some time on the mill and surface grinder  to reduce the thickness of the keys to 4.5mm.

That was quite a few peasant hours hours on the lathe, mill, and surface grinder, but the end result was good.

P1032877.JPG

The new servo motors, with the timing belt gears fitted, with keys in place.  I will set each motor in place on the CNC mill, determine the final exact position of the gear on the shaft, then indent the shaft for the grub screw.  Then, when I am sure that all is correct, the gear, grubscrew and shaft will be Loctited.

Another small issue was that the boss on the new motors was 5mm deep compared to 3.5mm deep for the originals.  So the mounting plate for each motor needed the recess to be deepened by about 1.5mm.

P1032878.JPG

I used a boring head on the mill to deepen the first one, but it did not produce a good finish, so the next 2 (shown) were deepened on the lathe, in a 4 jaw chuck.

Meanwhile, back to the rats nest in the electric control enclosure….

 

P1032875

The bare space top left is where the old servo controllers lived.  They were removed.  Then I spent a half day tracing each wire from the controller to the old servo, and removing it.  That produced a carton full of wires.  The rats nest is now a little less tangled.  A lot more of those wires will be removed as the job progresses.

P1032879.JPG

The new servo controllers bolted into position.  They are fatter than the originals, so a bit of rearranging was required.  The yellow box top right is the main spindle speed control (VSD) which is being retained.

P1032876.JPG

And on the right hand side, newly bolted into position today, from the top down, are the smooth stepper, the C11 breakout board, and two C10 breakout boards.   Awaiting some expert wiring.  (Stuart, are you reading this?)

 

Upgrading the CNC mill -3. Moving a threaded hole in steel plate.

P1032869.JPG

this is the new Y axis servo motor, sitting on its mounting plate, after the old servo has been removed

P1032863.JPG

Unfortunately the existing M8 threaded holes in the mounting plate are just in the wrong position for the new motor’s 8mm mounting holes.

So, do I 1. make a new mounting plate and assembly?   2. machine or file the new motor’s holes to fit the old plate?   Or 3. Fill the old mounting plate hole, then drill and tap new holes in the correct position  ??

  1.  seemed a lot of work   2. would have looked ugly and probably voided the motor’s warranty      3.  Seemed tricky, but I decided to give it a go.   If unsuccessful I could always revert to 1.

Filling the old holes.  Could have used steel thread and silver soldered it into place.  In retrospect, would probably have been the best option.   Could have used steel thread and Loctited it into place…. decided against, in case subsequent machining  softened the Loctite.   Could have filled the old holes with bronze, and drilled and tapped new threaded holes….   well, for better or worse, that’s what I decided to do.

The new holes impinged about 25-33% on the old holes.

P1032870.JPG

The old holes were bronzed.   I improved my technique as I moved around the holes.

P1032871.JPG

After cleaning up on the mill, the new holes were center drilled 

P1032872.JPG

Then drilled to size, and tapped.  revealed that the bronze did not entirely fill the voids. 

P1032874.JPG

I wondered if the bronze would accept a suitable degree of tightening of the M8 cap screws, but all seemed fine.   Note the jacking bolts, to prevent distortion of the weldment in the milling vice.

The bronze-steel sandwich did cause the tapping drill to wander slightly, but not enough to cause concern.  Next time I will try silver soldering in a steel filler piece.

Meanwhile, I have been removing parts and wires from the electrical enclosure.

P1032875.JPG

The servo controllers are removed.  Bit of a rats’ nest hey!  About 90% to go…

 

Installing the lathe gear

IMG_8080

I neglected to take a photo of the completed gear.  In this shot it is almost finished.

I intended to reassemble the spindle and its cluster of gears, spacers, and taper roller bearings myself, but after talking to an expert on the topic (Swen Pettig), I realised that sometimes it is better to leave surgery to a surgeon.

I gratefully accepted Swen’s offer to help.  In his working  life Swen had performed this task on many, many occasions.

Firstly Swen reinserted the taper bearing outer races in the headstock.  The lathe spindle is approx 80mm diameter and 800mm long so it is heavy.  After carefully cleaning, it was fed into the headstock, progressively loading the bearings, gears, spacers, clips and nuts, and moving and tapping them down the shaft as it was moved into place.

IMG_8113.JPG

Note the photo prints to remind us of the order of reassembly.  Board to protect the lathe bed.  Repaired gear laying flat.  Surgeons’ towels blue rags.

when it was all reassembled and tightened, the retaining disk at the chuck end was loosened, sealed with liquid gasket (Loctite product- cannot remember the name), and retightened.

Then Swen went through a lengthy process of checking the end play, using a dial indicator, tapping each end of the shaft with a copper hammer, and finally settling on 0.01mm of play.

Then we had a short test run at low speed, and he tested the end play again, with no change.

Then we set it running at 200 rpm, and went and had a cup of coffee for 20 minutes.  Came back and checked the bearings temperatures.   All cold, all good.

I reinstalled the external gears, the cover, etc, and took some decent cuts in some cold rolled bar.

All good.  Oil change soon.

 

German Battleship Helgoland – book review.

Seaforth Publishing, in association withThe National Maritime Museum Greenwich, is publishing a series of books of plans and history of famous warships, in this case the Helgoland.

GERMAN BATTLESHIP HELGOLAND

Detailed in the original builders’ plans

By Aidan Dodson

 

Wow!

I opened this large format, hardcover book of ship plans at midnight, expecting a quick flip through, and was able put it down 3 hours later.   But I will be returning.

The first 20 pages outline the development of German dreadnaughts and their wartime careers and fates, and a fascinating history it is.  The ship structure, armament, machinery (including engines), protection, pumping systems and damage control, and fire control are described in a degree of detail which was satisfying and not overwhelming to this non expert but interested reader-reviewer.

Then, all but 20 of its 144 pages are reproductions of the original builders’ plans of the WW1 German battleship Helgoland.   The plans are detailed, and beautiful and fascinating.  With original annotations in German, translated and explained in the margins.    The 940 x 290mm centre fold of the longitudinal section is just stunning!

Modelers, historians, ship aficionados, and anyone with a vague interest in battleships will love this book.  I certainly do, and eagerly await further volumes in the series.

IMG_8103.JPG

Front jacket

IMG_8106.jpg

Centerfold.  

IMG_8109.JPG

The German navy used triple expansion reciprocating engines rather than pay royalties to Parsons to use turbine engines.

CNC Mill Upgrade -2

The major components arrived this week, from China and USA.  Switches, and other components which go “ping” will be bought locally as required.  I am hoping that existing pulleys, belts, brackets will be adaptable.

The motors to drive the X, Y and Z axes are 1.2kW AC servo motors which can be connected to single or 3 phase power.  Each one weighs 6.7kg (14.7lb) .  From China, they are nicely finished.   Substantially shorter than the old servos which they are replacing and slightly larger diameter.  I am hoping that the slightly larger diameter will not cause major problems.

IMG_8088.JPG

AC servo.  There are 3 of these.  Kitchen knife to open the box and for scale.

IMG_8115.JPG

Old Y axis servo on the right, and the new AC servo left.

 

And each servo motor came with a controller and cables and connectors.

IMG_8093.JPG

And the electronics came from USA.

img_8096.jpg

C11 breakout board.

img_8097.jpg

C10 breakout boards x2

img_8098.jpg

And the Smooth stepper control board.  It is tiny, but the most expensive electronic component.

All up cost so far is ~$AUD2100, of which shipping is about 25%.

Next step is to swap over the servos.  The old shafts are 16mm and the new ones are 19mm.  I intend to machine the bores of the pulleys.  Hope there is enough meat  Tofu to allow that.

Cutting the Gear

Today Swen and I started cutting the gear.  Here is the setup.

IMG_8068.JPG

The gear was centered on the rotary table with an aluminium bush, which fitted the outside of an ER40 collet chuck.  The chuck had an M3 shaft which fitted neatly into the spindle of the rotary table.  3 bolts secured the gear blank to the T slots on the rotary table.

IMG_8085.JPG

This photo was taken after the setup was broken down.  Showing the M3 taper ER 40 collet holder, which I used to centralise the gear blank on the rotary table.

I started the mill conservatively at 200 rpm and a 0.5mm deep cut, but gradually increased the RPM to 450, and the depth of cut to 2mm.   Later adjusted to 300rpm, 1mm cut.

The CNC table performed flawlessly, with rapid advances between the 360/77º degree cuts (about 4.6º each tooth).  The feed rate was controlled by manually winding the X axis feed on the mill.

IMG_8074

We initially used water soluble cutting fluid, but changed later to raw Tap Magic, which seemed to work better.

As you can hear in the following short video, the cutter teeth are slightly off centre, but working well.  Didn’t quite finish the gear teeth in this session.  Some sparks later on, indicated that a cutter sharpening was required before the finishing run.  That will happen tomorrow.

The smoke is evaporation of cutting oil.

The setup will be left undisturbed by removing the gear cutter for sharpening.

I changed my mind about sharpening the cutter in the middle of the job, and continued cutting.

Instead, I lowered the spindle rpm, and the feed-rate.  The sparks stopped.  Maybe I was just pushing too hard, or maybe there was a hard spot in the metal.  Anyway, I finished the cuts.

IMG_8077.JPG

The finished gear cut.  Are those teeth looking a bit skinny at the peaks?

IMG_8078.JPG

Showing the setup from the operator’s view.  The CNC table worked brilliantly.

 

 

IMG_8080.JPG

Removing the burrs with wire brush and file.

IMG_8082.JPG

And testing the fit with a trial run in the headstock.  Thanks Swen, for helping (actually directing) the trial run.  The new gear on the left.

I made a video of the gear being rotated through 360mm, perfectly, but for some reason it will not upload.  (did upload eventually.. see below).    It looks perfect, with a tiny amount of backlash.   Full installation in a day or two.  I was quite surprised that making the gear to the specifications worked so well.

IMG_8084.JPG

Me, testing the backlash.

And afterwards, sharpening the cutter on the Quorn T&C cutter grinder which I made a few years ago.  An amazingly versatile tool.

IMG_8086.JPG

IMG_8087.JPG

Just in case I need to make another.

The lathe headstock will be properly reassembled in a couple of days.  But I am finally feeling a bit confident about this job.

 

 

 

Not Antarctica Again! Groan…

For those readers who have not automatically skipped this post after reading the title, I had some time to spend on Google Earth Pro recently, and back to my area of interest, at the big black reflective rectangle 22 x 7km, photographed in 1999.  And the strange 300 x 150mm objects seen 2006 – 2007.

This time I went back a few years to 2002, and this line of objects caught my eye.

Screen Shot 2019-07-08 at 1.57.18 pm.png

This is Antarctica, Dec 31 2002.  The red, yellow and blue pins are 300 x 150m objects, seen 2002-7.  The big black rectangle is in the middle of the left hand cluster.   The area of today’s interest is the small red line to the left of the long red line.  The small red line, placed by me on the photo, is 20km long.   The next photo is zoomed in to the small red line…

Screen Shot 2019-07-08 at 1.57.43 pm.png

Still 2002, small red line. Those 21 black dots are 1km apart.  And there is another, to the right near the top of my red line.   Now to zoom in some more…

Screen Shot 2019-07-08 at 1.59.17 pm.png

Look at those shapes.  They are 300 x 300m each.  Similar but not identical to each other.  Exactly 1 km apart.

The black rectangle does not appear in these 2002 photos.

The co-ordinates are bottom right, so you can check this out for yourself.  What do those black shapes look like to you?   Unfortunately zooming in closer does not increase the clarity.

Now, do you want to know how I found this second row of objects?  This is where it gets even more interesting.

There appears to be a track or mark in the snow leading away from the big black rectangle, leading to the south east at heading 112º.  The track is 7km wide, the same as the black object.   I followed it on Google Earth, until it disappeared after 132km.  At that point on Google Earth I scanned the years 1984-2016.   And zoomed in and out.

And guess what!  That point is exactly where the row of 21 objects which are 1km apart, starts (or ends).   WTF?!

And just to complete this post, there is a site on YouTube which I have been watching with interest, called “Bruce Sees All”.  “Bruce” is an amateur astronomer with a decent telescope which he has been pointing at the moon, and making videos.  I have taken some screen shots, which I post here.  Hopefully this will stimulate some of you to go to the YT site and check it out for yourself.

Screen Shot 2019-07-06 at 10.03.51 am.png

No scale unfortunately, but that white donut shape must be many kilometers wide.  And by the shadow which it is casting, it is way above the surface.  Similar shapes nearby.

Screen Shot 2019-07-06 at 10.15.29 am.png

And look closely at all of the rectilinear shapes in this screenshot.  Square meteorites perhaps?

 

I will get back to gear making tomorrow, hopefully.

Preparations for gear cutting

Almost ready to cut the lathe gear.  It is 237mm diameter, 25mm thick, with a new rim Loctited and Scotch pinned to the old hub.

IMG_8061.JPG

I borrowed the 6-12″ Mitutoyo micrometer from a GSMEE member.  Thanks Rudi.  I had to learn how to read an imperial micrometer.  The rim is glued and pinned to the original hub.

And today I made a tool holder for the new-old gear cutter which I purchased from Russia.  It was meant to have a 27mm bore, but when measured was closer to 27.1mm, so I made an arbor to match.

IMG_8062.JPG

The cutter on the new arbor.  It required 2 attempts to get acceptable dimensions. It will be held in the vertical mill with an Er40 collet chuck.  It runs true.   Not bad for an ex gynaecologist hey?   Might need to sharpen the teeth on this old-new cutter.

Meanwhile, on advice from Swen, another GSMEE member, thinking ahead, and setting up to trial fit the new gear after it is cut.   Here is Swen, making some steel temporary bearings to try the new gear on the shaft, after the gear is made.  Tapping out the old taper bearing races.   This is what Swen did for a living when he was in the work force.  I have learned heaps just watching Swen doing his stuff.

IMG_8055.JPG

I admit that I would not have been brave enough to do this.  “Piece of cake” says Swen, tapping out the race with a copper drift.

CNC rotary table and preparing a gear blank

Hi readers.   Sorry for the long break.  Since my return from UK I have been severely jet lagged, then very busy, and not much time in the workshop.

The jet lag going westwards to from Oz to UK was minimal, but after the homeward trip it took 2 weeks to start feeling normal again.  It is a 22 hour flight, plus 2 hour stop over in Singapore.   I do not remember ever having such marked jet lag before, and  not much was done during those initial 2 weeks.

When I did venture back into the workshop, I discovered that my CNC mill was malfunctioning.  The Y axis has been a bit unpredictable for quite a while.  I found a broken wire and fixed it, but the problem returned.  After a previous electronic failure in the Z axis, my CNC expert advisor, Stuart,  suggested that I should  replace the electronics in a major upgrade.  The mill is a solid industrial machine, mechanically in sound condition, and is worth spending some time and money on.

It is a 1997 model, and the memory in the CNC motherboard is a whopping 7k!  I was able to get a fair bit done with the 7k, and the situation was improved by linking an external PC, and using V-Carve Pro.  But there was a limitation in that the mill is a 2.5 axis machine.  Not that I want to use 3 or 4 axes very often, but the lure of improving the mill is irresistible.

So I am in the process of ordering 3 new servo motors.  They will be AC single phase servos, rather than 3 phase motors.  I have installed one of these in my small Boxford lathe as a spindle motor, and it has proved to be reliable, compact, powerful and inexpensive (well, fairly inexpensive, comparatively speaking).  They have been ordered from China.  Cost-wise, the three axis motors will be much less expensive than one of the existing 3 phase servos.  On top of that I will need a breakout board, ESS smooth stepper to link to a computer, and various switches, wiring, power supplies etc.

I will document the steps of the rebuild.

But the item that I was getting to, was hooking up my rotary table to CNC.  I had expected to pick up a new gear for my big lathe on my return from the UK, to replace the one with the broken tooth.  I was pretty annoyed to learn that the gear maker had not done the job, and worse still he had not notified me that it had not been done.  Since he never answers the telephone, I drove to the factory, expecting to pick up the new gear, as arranged and promised, to be met with apologies and excuses.  Long story, I have decided to make the gear myself.

It has 77 teeth, an unusual number for a gear, which means that it has to be made, not purchased off the shelf.  I have a dividing plate with 77 teeth, but I could see plenty of potential for making mistakes using that, so I elected to finish the CNC conversion of the rotary table which I had started last year.  The mechanical aspects had been finished.  All that was required were the electronic hookups.   Fortunately for me, I have a friend who is an expert at these.

P1032849.JPG

In the center is the rotary table, an 8″ Vertex.  The stepper motor is a NEMA 36.   The intervening aluminium block is the coupler.  The controlling program is Mach 3.  Originally I intended to use an Arduino, but it seemed more complicated and less robust than this setup, which involved using the breakout board of the CNC lathe (right), and a new Gecko driver. (see next pictures)

P1032855.JPG

P1032853.JPG

Looks complicated and messy.  Much better with the doors closed.  The rotary table Geckodrive is the one on the left.  The 2 on the right are for the lathe.  The black white and green wires 8,9,10, are from the breakout board.  The black and red 1 and 2 are from the 48v power supply, and the stepper motor power is from Windings A and B, 3,4,5,6, in the thick white wire.

I confess that I have little understanding of the wiring.  Stuart had it hooked up in under an hour.  A bit longer configuring and tweaking Mach 3, and it was working.  The extra Geckodrive, and some wires were the only extra components required to make the electronic connections.

I shot a video of it working, with giving a commentary.  But it is so bad that I will reshoot it, and add it to this post in a day or 2.   Sorry.  Not done yet.   But I have been busy preparing the blank for cutting a new gear.

I decided to retain the hub of the gear and to add on a new ring which will be machined, and then new teeth cut into it.

Firstly I had some 25mm steel plate water jetted approximately to size.  I chose water jetting in preference to laser cutting or oxy-acetylene cutting to avoid any inadvertent heat hardening.

I also had the original gear water jetted to remove the outer 25mm, including the teeth, because it had originally been heat treated hardened, and I did not fancy machining that on my other lathe and maybe breaking more teeth!

It was not cheap.  But a nice finish, which machined easily.  So the hub and the blank ring were machined with a 0.1mm gap, and glued together with Loctite 620.  Then Scotch pins were inserted.   Since my CNC mill is out of action, I reverted to calculating X and Y co-ordinates, using FS Pro.  See screen shot below.

 

IMG_8057.PNG

My CNC mill is out of action, so I reverted to doing some XY calculations on the manual mill with DRO, using FS Pro.   Screen shot above.

 

IMG_8056.JPG
And in the above shot, I have drilled and threaded some M6 holes and Loctited in some M6 grub screws.

Then machined it to size,

IMG_8058.JPG

The 6mm holes are the Scotch pins.  The 10mm holes are to attach the assembly to the CNC rotary table for cutting the teeth.

So, this post might be a bit ramshackle and disorganised.   A bit like my workshop at present, and possibly my brain.  My GP has started me on blood pressure medication, so I will blame that.

Watch this space for cutting the gear, soon.

 

Google Earth Antarctica Photos

Google Earth used to update the Antarctica photos annually, on 31 Dec each year.  BUT NOT SINCE 2016.

WHY NOT?

What is going on down there?

CNC Mill Upgrade

I was not planning any more major projects for 2019, instead intending to finish the triple expansion engine, the beam engine, the vertical boiler, and the CNC rotary table.

But… my hand has been forced.

The Y axis on my CNC mill has been a bit unpredictable for some months, and on my return from UK, it has totally stopped working.  It seems to be the encoder on the Y axis servo.  I could just repair or replace the encoder, but after discussing the situation with my expert advisor Stuart, I have decided to replace all of the electronics in the mill.  New axis motors, new breakout board, new drivers etc.  It is a 1997 model, and this is the second electronic failure this year.  Plus, it is only a 2.5 axis mill.  It will move in only 2 directions per move….   XY or XZ or YZ,  never XYZ in a single move.   Plus I would like to add a rotary axis, making it a 4 axis machine.

The in built computer in the mill has a 7k memory.  That’s correct, 7000 bits.  I have an external computer linked to it, which makes it a bit more useful, but the Fagor controller is clunky and idiosyncratic, and I would like to switch to Mach 3.

So, I will document the upgrade as it happens.  The mill is a good solid machine, with big ball screws, and 1000mm of x travel, 450mm Z and 450mm Y.  It is worth spending some money on it.  There are a lot of big, old, CNC machines with obsolete electronics out there for sale.  It will be a project which might just be worth watching.

Showing the handwheels for XYZ axis movements, including the broken X axis handwheel

 

Back to the Trevithick Dredger Engine Model – the lagging.

The only surviving Trevithick dredger engine, in the London Science Museum, shows no signs of ever having been lagged.  I know this, because I examined it closely, recently, during my UK trip.

No lagging, no marks in the paintwork, which would indicate wooden lagging strips ever having been attached.

But, we know that Trevithick readily adopted ANY improvements to his designs, and lagging was appearing on engines at about the epoch of the dredger engine design. Plus, his engines were in use as late as mid 19th century, and lagging was well established as a normal feature by that time.

And, my model definitely needs some efficiency improvement.  Using a 40kW burner to power an engine of this size is ridiculous.   So I Have added some lagging.

P1032772.JPG

Equipment for applying lagging, from the left…   scroll saw, super glue (I used 6 tubes), strips of wood (in this case, Australian Jarrah, grinder for shaping, Dremel for shaping, good light, and the engine with some of the strips glued in place.

I used about 48 strips of wood with some spares.  These were cut and sanded in advance.  5mm x12mm x 130mm.

The Super glue is used to hold the wood strips in place temporarily, until the brass boiler bands are installed.

I started at the top, and worked my way down on both sides.  Most effort is made in fitting around  pipes and boiler bosses.  Unsatisfactory strips are levered off and scrapped.

P1032773.JPG

A rebate was milled on every wood strip, to permit removal or tightening of the boiler end plate nuts.

P1032774.JPG

I used rubber tree ties to maintain pressure until the glue dried, but in most cases I just applied finger pressure until the wood stuck fast.

P1032775.JPG

Some pipes and fittings necessitated grooves being made with round files.

Super glue does not provide a permanent bond to copper for some reason.  And it certainly will not survive the heat from steaming.  But it is fine for a quick and temporary bond.

P1032776.JPG

After making and applying the brass boiler bands (this was covered in the “6”vertical boiler” posts) I used olive oil to seal the wood.  See discussion which follows.

I chose olive oil to seal the grain openings of the jarrah.  I know from previous firings that the temperature of the boiler shell does not exceed 100ºc.  Olive oil will not smoke or flame until the temperature exceeds  200ºc, which is higher than any other common oil.  Also, as a failed olive farmer, I have plenty of old olive oil.   At worst, my engine steamings might smell like a fish and chip shop.  And refreshing the oily surface will be quick, cheap and easy.  And the olive oil will not form a skin which might peel or flake.  Anyway, this is “model and experimental” engineering.  If it does not work, I will make some new lagging, alright!.

And I took some more photos with my Panasonic Lumix 100-2 camera…….

P1032781.JPG

Still some more painting required to the end plate, and some fittings.

P1032808.JPG

That domed boiler end with the cylinder protrusion also needs some paint.  But the lagging looks good hey?

Even SWMBO has relented…  “It can go with the other engines”.  It will, when it is finished.  Still requires more painting.

Model Engineers have Other Interesting Hobbies.

When I visited York, UK recently, I met up with a reader of the blog, Jennifer Edwards.  Jenny had set aside 2 days, and we visited the Kelham Island industrial museum in Sheffield, and the York Railway Museum, both of which have featured in recent posts, and both of which were wonderful.  It was made much more enjoyable by having a kindred spirit as company.  And fortunately both of these sites were new to Jenny also, and equally enjoyed by her I believe.

P1011015.JPG

Jennifer at the 12000hp steam engine, Kelham Island.

This post is about one of Jenny’s many interests.   Metal detecting.

I am not sure what attracted Jenny to this activity, but she joined a local detecting club, and spent many days checking English fields with the club, searching for interesting metal objects.   With fairly limited success.

Then one day she had the idea of checking a local rugby pitch.  Surprisingly, the rugby club agreed, with some stipulations I am sure, about replacing turf, minimal disturbance etc.

Within a short time, Jenny was getting positive signals, then carefully cutting out a square of turf, then digging out the ground, in most cases no deeper than about 150-200mm (6-8″).  And finding coins, rings,  (gold, platinum, some diamond), musket balls and other interesting objects.  Obviously, the field had never been previously scanned.  And research later revealed that the area had been the site of a village fairground.   And before that a walled area for defence against sea raiders.  Very old apparently, because some of the coins were Roman.  Others were of later vintage, medieval, Victorian etc.  About 200-300 objects of interest were found by Jenny.

The find was unusual, and was written up in a metal detecting magazine. (The Searcher, September 2018).

Jenny showed me some of the oldest coins, and I was flabbergasted when she said that I should keep one, as a memento.  I did say that I couldn’t possibly… but I confess that holding something so old, much less being given it, was overwhelming.  I accepted.

Here are some photos of the coin.  It is a silver denarius, minted in Rome in 137BCE.  i.e. it is 2156 years old.  Minted in the Republican era, before Julius Caesar, before Christ.

Tampil.png

The image is of Apollo.  “Tampil” is the family name of the minter.

Baebius.jpg

The reverse shows Apollo on a 4 horse chariot, holding a laurel branch in one hand and a bow and arrow in the other.  The words “Roma”  and “Baebilius” (part of the minter’s name) are clear.

The coin is small (about the size of an AUD 5 cent piece), silver, and the images are amazingly clear.  The Tampilius family was well known, having provided senior officers for the Roman infantry, and at least one consul of Rome.    The right to mint coins was granted to some high status private individuals in ancient Rome.  The value of the coin was roughly equivalent to its value in the silver it contained.

It says heaps about Jenny’s  generosity that she gave the gold and platinum rings to the rugby club.

 

 

 

 

Modelling Jeeps and Tiger Tanks (books)

I received 2 more books from Pen & Sword  for review, and these are both directed squarely at modellers.  They both contain interesting information about their use in WW2, but are mainly about the external appearances, and configurations.  Not much information about manufacture, strategic importance, or mechanical aspects.

p1032765.jpg

THE JEEP

Second World War

by Lance Cole

 

This large format, 64 page book is written for Jeep enthusiasts, Jeep modellers, and Jeep restorers.

This reviewer is an experienced 4×4 driver and owner, and interested in WW2 vintage Jeeps from an historical perspective, and for technical comparisons.

The book will have enormous appeal to its target audience, but less so to the casually interested reader like me.  It does include some general historical notes and comments, but these seem incidental to the main subject matter, which is about modelling of the body work and weapons.

There are many photographs of Jeeps in wartime configurations, and mounting various weapons.  Also lots of photographs of model Jeeps.

Modelers and restorers will love it.

p1032766.jpg

P1032770.JPG

 

 

TIGER 1 AND TIGER 11 TANKS

German Army and Waffen-SS

The Last Battles in the West 1945

by Dennis Oliver

p1032767.jpg

 

This is another of the series of Tank Craft books which aims to provide model-makers and enthusiasts with photographs and line drawings of battle tanks which are popular subjects for modelling.

The 64 page , large format book has many such images, as well as notes about the military actions, as far as is known, of the German Tiger tanks in 1945.

The illustrations are of the tank exteriors only.  They are detailed, colour and of high quality.

A 15 page section lists and assesses commercially available kits from various countries.

Tiger Tank modellers and illustrators will love it.

p1032768.jpg

P1032769

 

 

 

 

 

 

%d bloggers like this: