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.

Tag: Adept lathe

TNC lathe restoration completed.

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Miniature lathe mounted on an aluminium base, and hooked up to a new, variable speed motor. The pulleys were turned from aluminium.  The motor is controlled with a foot switch.  

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Headstock detail, showing the thrust bearing between the chuck and headstock, oil wells, pulleys and belt. I expect that an ER16 collet chuck will be used more often than the 4 jaw chuck.

TNC Lathe restoration progress

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The before picture.

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Current . After cleaning, holes filled, painting, new handles, new spindle shaft, new oil reservoirs, chuck refurbished, some parts nickel plated, new base. Gibs resurfaced. It all moves smoothly, with minimal backlash.

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Mounted on an aluminium base. Ready for its new motor with foot operated speed control and headstock pulley to be turned. I installed a thrust bearing between the chuck and headstock.

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TNC Lathe renovation 3

SWMBO has “persuaded”me to make two sets of double gates for a Norlane renovators dream, so not too much happening in the machine shop.  Welding and cutting in our Australian summer is not fun.  The gates are ready to be hung so hopefully I might be allowed back into the play area in a couple of days.

I did get a few hours to put some colour onto the TNC lathe.  Dark green enamel sprayed with a “Badger 360” air brush.  First time.  Fun.  Not a fantastic result but OK.

I was quite impressed at how effective masking tape was, in keeping paint off machined surfaces.

This whole exercise is a practice run, so I minimise the chance of stuffing up when I paint the Beam Engine.

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Spraying the tailstock.  The other hand is holding the iphone camera.

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The Badger 360 in an aftermarket cleaning tank.

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The lathe bed and headstock with 2 or 3 coats of topcoat. The big bolts with nuts are to keep paint out of the bearings.

TNC Lathe renovation 2

Some progress on the little lathe.

A complete disassembly, and separation of the parts to be repainted.

Some unwanted holes were filled with steel putty (similar to JB Weld), and filed flat after hardening.

Then further filing of the parts, a soaking in degreaser, and then a wipe over with acetone.

Then a coat of undercoat, from a spray can.

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Can hardly see the repair

Can hardly see the repaired holes through the undercoat.

Making the larger handle, the one for the leadscrew was a learning exercise.  I planned it in brass, with a counterweight to the handle.  Drew it up on CAD, then tried to make it using the Boxford CNC.  The end result is not perfect, but it will do.

IMG_2443I discovered that it is quite difficult to turn complete balls on each end and avoid chatter.  I used a carbide cutter.  Perhaps HSS would have worked better.

First result goes in the rubbish bin.

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Actually it will go into the odd brass bits bin in case it can be used for something.

I finally turned one end, then made a split collet, and turned the other end.  All done using CNC.

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Did not entirely eliminate the chatter.

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The partly completed workpiece, held in a taper split collet, which was held in an ER collet, which was held in my home made collet chuck.

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It will just have to do.

TCL lathe renovation 1

I CNC’d a new handle to replace the broken one on the little lathe, but the new one made the old ones look a bit shabby, so they will all be renewed.  The new, deeply waisted handles are very nice to use.

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The headstock shaft was 3/8″ and was a bit undersized due to wear, and I intend to use a collet chuck with a 10mm shaft, so I decided to increase the shaft size from 3/8 (9.525mm) to 10mm.

The headstock bearing housing is split, to permit some adjustment with wear.  I used a reamer with spiral teeth to avoid the teeth snagging the split.  And all seemed to go very well using the setup in the photo below.

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…Until I finished and raised the milling machine head out of the work.

Due to my lack of familiarity with the CNC mill controls I  activated the X axis rather than the Z axis.  The side movement broke the reamer and partially gouged the newly reamed lowermost housing.  Bugger.  Bugger.

What to do.  Throw the whole project into the scrap bin?  (following a few others).  Change the shaft to the next size (12mm) and enlarge the housing holes to 12mm?  That would thin and weaken the housing.  And would be tricky machining.  Also, due to the damage in a lateral direction caused by the mishap, I was not sure that drilling and reaming, or boring and reaming, would not follow the same lateral path.

At least the uppermost housing  was undamaged, so whatever tool was used would be held concentrically, as long as the cutting edge extended the distance between the 2 housings.

So I very slowly drilled 11.5mm (the 11.5mm drill did span the distance between the 2 housings) and re-reamed to 12mm, again as per the above photo. Despite my misgivings, this time it all went well.   The 12mm shaft is rather tight, and the housings will need some lapping.  The housings appear to have enough thickness remaining, but time will tell in that regard.   The lateral direction of the shaft is not perfect, but in such a small lathe that is not a big consideration.

As a consolation, and to retore some self esteem after this muck up, I made a new chuck key.

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The chuck is held onto the shaft with a 3/8″ x 24tpi thread.  That thread was cut on the CNC lathe, and is probably fairly accurate.  The oil cups are spare from the beam engine build.

I plan to lap the housings, install a thrust bearing behind the chuck, and make a drive pulley.  I have a spare 12mm shaft ER 16 collet chuck, which will probably be used more often than the 4 jaw chuck.  Then a new handle for the longitudinal feed, a paint job, a motor and belt…