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.

Category: Tools.

TWO WORKSHOPS

This post was inspired by one of my readers sending me some photos of her workshop.  The photos grabbed my attention for several reasons.

Firstly, the metal working machines share the space with tomatoes!  Unusual, eclectic use of the space.  Secondly, the roof and walls are made of glass!   Great for natural lighting, and nice views for the machinist, and possibly the neighbours.  Thirdly, it is such a small space, requiring planning to accomodate quite a few machines and work space.   And fourthly, it is so neat and clean.  I do see an occasional bit of swarf, but it is so unlike the mess that I work in, that it is quite striking to see such a clean workshop.

Thanks to reader Jennifer for sending these photos.  For obvious reasons I will not publish further location details except to reveal that the location is in the UK.

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Jennifer tells me that it is all double glazed, and is open to the living area of the house, so it is heated.  Apparently it never becomes too hot in summer.

And as a complete antithesis, this is my main workshop in Oz.  Bigger, messier, dirtier, darker.    Actually, when I looked over my photos I could not find one decent view of my workshop, so I took some new pics.  Needless to say, there was no special tidying for the photo.

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It is a tin shed, unlined, but does have a wood heater.  This view takes in about 2/3 of the area.  There are 3 lathes in this shot.  Can you see them?  CNC lathe in foreground.  Also my CNC mill on the right.  There is also a tool and cutter grinder, vertical bandsaw, drop bandsaw.  And lots of ancillary tooling.

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And a pedestal drill, 2 linishers, grinder, and part view of the drop band saw.  The anvil gets quite a lot of use.  It is mounted on heavy duty wheels so I can take it to the job.

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My workbench in the foreground, A very heavy cast iron setup table (blue) with granite surface plate.  Shop made ring roller centre.

So, that is where I spend most of my waking hours.  The shed started life as a farm workshop, where a lot of welding, and repair and maintenance of farm machinery was done.   These days it is mainly used for model engineering.  In my working life I was an obsessively neat, organised and particular surgeon.  Not quite sure how my activities ended in this mess.  But you know what?… I feel totally comfortable here.

 

 

If you have some photos of your own workshop area, please send them in and I will publish them for the interest of other readers.  Big areas, small areas, old machines or new.  Show us where you spend your most enjoyable hours.   Send them to me at jviggers@iinet.net.au

 

 

 

 

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.

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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.

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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.

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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).

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

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

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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.

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

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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…

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The bolt adjusts the height of the jack.

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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….

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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…

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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.

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Stuart, doing another CNC upgrade wiring.

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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.

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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.

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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).

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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.

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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.

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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.

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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….

 

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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.

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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.

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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.

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

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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.

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

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

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

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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.

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

 

Installing the lathe gear

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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.

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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.

 

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.

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

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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.

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And the electronics came from USA.

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C11 breakout board.

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C10 breakout boards x2

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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.

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.

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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.

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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.

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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.

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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)

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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.

 

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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.

 

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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,

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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.

 

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

 

Lathe Woes

Removed the gear with the broken tooth from my GBC 400-1000 lathe yesterday, with some help from my brother.    Approached the disassembly a bit nervously.  Did not want to break or damage anything else.

First took some photographs, so I can put things back together eventually, in the correct places and order.

Then removed the chuck, then the back gears, then the large heavy plates at each end of the spindle.  The cap screws came out without any drama, but the end plates required breaking free of the paint, and out of the tightly fitting mounting rebates.

Then loosened the big nuts against the internal gears, the external gears, and one grub screw.

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Tabbed locknut undone, allowing the gear cluster to be slipped and driven towards the left, eventually allowing the spindle to be removed.

Gradually removed the spindle by tapping the gears along the spindle with brass drifts.  Pretty tight.  And retrieved the little bits as they fell into the oil in the headstock.

Was finally able to lift the spindle out through the chuck end of the headstock.  It is heavy.   Took two of us to lift it out without damaging the outer races of the tapered roller bearings.

Then looked at the broken gear, and retrieved the tooth from the headstock oil.

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The broken tooth.  Unfortunately, on closer inspection, and adjacent tooth is also cracked.  And very likely more are on the way.   This is more serious than initially thought.  It is a big heavy gear, 240mm dia, with a 65mm long collar,

Next step was to look closely at the meshing gear.

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With a good light, and getting close I still had trouble checking for cracks.  Only when I looked at this photo did I realise that I had forgotten to change my sunglasses.   Ah, the joys of getting old and forgetful.

Meanwhile, I remembered a tool which might help with the inspection….

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It is a cheap fiberoptic inspection camera.  Worked fairly well here, and I am reasonably happy that the other gear is not cracked.   But it did convince me that I should have bought a better quality fiberoptic camera.  Put it on the wish list.

So, I have a large, hardened steel gear with at least 2 cracked/broken teeth.  Options?….

  1. Buy a new gear.  I will try, but not confident.  The local importer of these particular Chinese lathes went out of business last year.
  2. Get a new gear made.  I will get a quote.
  3. Make a new gear myself.  Or, if all else fails….
  4. Machine off the teeth of the damaged gear, and the adjacent 20-30mm.   Then make a new set of teeth on a ring which will be attached to the old core of the damaged gear.
  5. Use the lathe without that gear.   This option does not appeal.
  6. Install a VSD and use electronic control of spindle speeds.  The main spindle motor is 5HP, so it is possible.

More information required.  Watch this space.

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Back in the workshop, a Lathe Problem…

I have a problem with my big Chinese lathe.  I was hearing a KNOCK-KNOCK-KNOCK as the main spindle was revolving at low speeds with one setting of the gears.

It is a GBC 1000-400 lathe, meaning that it has a maximum of 1000mm between centres, and it will turn a 400 mm disk.  It weighs 2 tons.  Has been quite useful when turning flywheels, big lumps of metal, large pieces of wood and so on.

So today I removed the cover from the headstock and had a look.   The cause of the knock was quickly obvious.

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The headstock of the GBC 1000-400

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The big gear on the main spindle at bottom.   See the broken tooth?  The meshing gear is intact.

So, what do I do about this?   I need some suggestions, people.

Thoughts so far….

  1. remove the spindle, remove the gear and bronze braze a replacement piece of steel or bronze, then machine a new tooth.
  2. same as 1, except use silver solder.
  3. same as 1 or 2, except do the job insitu (after draining all of the gearbox oil, and screening off the other headstock parts).  Unfortunately the missing tooth is close to the headstock case, so filing or grinding a new tooth would be tricky.
  4. leave it as is, and just avoid using that gear.  I can do that.  It removes 3 of the 9 gear ratios, including the slowest speed (40 rpm), and is not an elegant, or desired solution.

So what do you think?   The gear is most likely made of steel rather than cast iron, from its appearance.  The base of the break is shiny, smooth and not porous.

Here are some pics of the ends of the main spindle.   It does not look too complicated to remove the main spindle, but what would I know.

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The main spindle is the one in the centre.

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And the other end, with a self centering 4 jaw in place.

I imagine that the main spindle bearings will be pre-loaded, tapered, roller bearings.  I certainly do not want to damage them.  And how difficult will it be to reinstall the bearings and main spindle?   I imagine that it will involve some careful and precise work.   Am I taking on a job which is way beyond my abilities?   If anyone has experience of this task I would be delighted to hear your views.   I have no drawings or plans of the headstock to assist.

(In parentheses, when I was a teenager, I remember my father pulling a Toyota Crown automatic gearbox to bits, identifying a fault, and fixing it.  There were bits of the gearbox everywhere.  But he fixed the problem.  He was not a mechanic, but he had a go at things, and usually managed the task, as in that case.  Similarly, I dont mind having a go at this lathe job, but I would prefer not to risk destroying the lathe, so any expert opinions will be welcome.   Option 4 above remains a possibility.)

 

Beware of Greeks Bearing Gifts

Well, this one is OK because it came from a Hollander.

One of my blog readers, Huib, decided that I would be the recipient of some of his workshop items which he says were surplus.  This was as a thank you for johnsmachines.com.

So, a parcel arrived yesterday, and after a quick look inside, I decided to make a video of opening the items, and showing you.   It was great fun for me, and I hope that it will be entertaining for you.  It is the biggest file which I have uploaded, so give it a few minutes to open.

 

(This is the longest video which I have uploaded, and I have now deleted it to make some space at my WordPress storage, which is almost full.)

Oh, any other readers who would like to send me surplus tools or other interesting bits and pieces….  please feel free.  If Haas, or Hardinge would like a review on one of their machines please send it and I would be happy to do a review.

A Long Drill Bit

I have not been looking forward to attaching the Trevithick Dredger Engine to its base.

I needed to drill through the steel plinth and the wooden plinth, and then through the top part of the base.  Trouble was that the boiler and engine were in the way.

And it was not feasible to tip the whole assembly upside down and drill from underneath.

Ahah! what about a long drill?   I measured it.  The drill would need to be 450mm long!  Even a long drill bit, ferociously expensive, comes at a maximum length of 150mm.

So, I made a long drill bit, 5mm diameter, 600mm long

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That is a new 5mm cobalt drill bit, silver soldered into some 8mm drill rod.  Could have been a bit shorter, but it was long enough.

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Using the long drill bit, I was able to drill through the steel support, and through the top wooden layer of the base.   Then bolted the parts together.   And was then able to place the engine and the wooden layer on their ends, and to drill the remaining holes from below, confident (fairly confident anyway), that nothing could go wrong.   As in the above picture.

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Meanwhile, I had added the valve which controls the boiler feed pump output, and connected it to the boiler feed pump.

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Boiler feed pump valve.  This valve was left over from the vertical boiler project.  Just right, when I have repainted it.

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Next I must drill a 5mm hole through all layers of the base.   150mm!  4 holes, one in each corner.   The long drill made today will not do because the 8mm shank is too thick.   I must make another long drill, with a 5mm diameter shank.  Watch this space!

 

 

New Oxy-Propane Torch just watch!

Yesterday I took delivery of a tiny oxy torch.  I guess that most buyers would be jewellers,   but if you watched my post about silver soldering the tiny Trevithick dredger engine firebox door hinges, you will understand my interest in this Ebay offering for $AUD28.

I am experimenting with making videos for this post, so please excuse the amateurish faults in the following videos.

And here I am experimenting with the tiny torch.  Frankly, It is probably not up to the job here, but it was interesting trying it.  I can see that it will be very useful for other small jobs.

Please excuse the awful video technique.  I can see that I need a better camera, tripod, and technique.

This little oxy – propane/acetylene/MAPP gas/hydrogen/ etc is pretty awesome.

And BTW, the leak in the water pre-heater was fixed!

6″ Vertical Boiler. Calibrating the pressure gauge

I bought 2 pressure gauges at a recent Model Engineering Club auction night.  I paid $AUD40 for the pair, although I was really only interested in the smaller one.

It was a bit of a gamble.  Would they work?  Accurate?

Stuart mentioned that he had an instrument for calibrating gauges, and he checked my gauges.

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This gauge was item 51 at the auction.  It is about 4″ diameter and has some style!   Brass of course.   The cream painted instrument with the shiny brass weights is the calibration gauge.  It confirmed that my gauge was spot on at pressures of 50, 100, 150, 200 qnd 250psi.

The smaller gauge, 38mm  1.5″ diameter which I will use on the Trevithick dredger engine, was not quite as accurate, being 2.5psi out, but is adequate for use.  It is also British made, brass, and nice appearance.

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6″ Vertical boiler. 2nd Braze

Today was cold, wet and windy. so the wood heater was started when I arrived at the workshop.

Then a couple of hours using emery paper and steel wool to get shiny copper surfaces ready for silver soldering on the vertical boiler.  Then copious application of flux to the surfaces.  Loose bits held with iron wire.

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A slight re-shaping of my forge to accomodate the shape, and allow access to the top front and sides.

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Not so pretty after applcation of heat from the oxyacetylene torch and the weed flamer at the same time.  Both hands were fully occupied, so no action photos.

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And after the usual sulphuric acid bath and rinse.  A couple of joins need to be redone, and then a test for leaks.

Reader and GSMEE member Ian asked about the cam lock clamps which I used in a recent post.

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They are “KNU-VISE” clamps, used in aircraft manufacture I believe.  I bought a box full of them in Ebay’s early days, when bargains were still to be found and US postage was not prohibitative.  Very useful for powerful clamping up to about 50mm.

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