M type lathe tumbler reverse

[David George 1Participant @davidgeorge1]

I acquired some castings for tumbler reverse so started machining first casting.

Held in 3 jaw chuck skimmed machining boss and centred to hold square and machined outside to size.

Skimmed inside face to help hold whilst cutting radial slot etc.

Turned round to face boss to length and bore to size for spindle.

David

[David George 1Participant @davidgeorge1]

[HopperParticipant @hopper]

Good work for an 80-year-old "hobby" machine.

[geoff walker 1Participant @geoffwalker1]

Excellent work, nice castings!!!!!

Geoff

[David George 1Participant @davidgeorge1]

Next set up on rotary table for milling.

David

[David George 1Participant @davidgeorge1]

Finished machining radial work on main casting.

David

[Michael GilliganParticipant @michaelgilligan61133]

That's looking good, David

This thread should make a useful 'masterclass' reference for some tricky-looking jobs.

MichaelG.

[David George 1Participant @davidgeorge1]

Now to turn the boss to length. Hacksawed the boss waste off and made a expanding shaft jig to hold the part. Piece of size material, centre drill with large drill to make 60 deg cone and tap M8 for screw. Turn 60 deg on back of head on cap screw. Hacksaw two slits to allow diameter to expand. Debur and screw in screw check amount of expansion, loosen and put on part tighten to grip part and check that it won't slip, OK.

 

 

Put in lathe chuck turn to length and the main casting bar drilling for pin on assembly us done.

 

David

 

Edited By David George 1 on 23/03/2019 17:43:39

[David George 1Participant @davidgeorge1]

Started work on quadrant casting.

Fly cut the casting to thickness and then clamp down to bore the holes for gears.

Finally bore the shaft hole for support shaft.

David

[David George 1Participant @davidgeorge1]

Started to drill the quadrant casting edge holes. As the hole for the location plunger has to be at 112.5 degrees to gear holes I used a sine bar to set the angle. The hole has to be in relationship to shaft hole so bolted a short length of shaft to angle plate and centred mill on shaft. Put casting on to shaft, rotated to suit the sine bar and clamped problem solved.

David

[geoff walker 1Participant @geoffwalker1]

Nice work David,

I admire your methods and attention to detail.

I suspect this will be the most accurate T.R. ever made!!!

atb Geoff

[Howard LewisParticipant @howardlewis46836]

Looking good! Very well done!

Howard

[David George 1Participant @davidgeorge1]

Done a bit more on tumbler reverse, made the turned parts and started drilling and milling them to get them to work and the small gears have arrived so I can try to fit it and set it up for drilling for taper pin to fix it rotationally. I drilled and tapped the main casting for a grub screw to help with holding it whilst setting it up.

David

[Nicholas FarrParticipant @nicholasfarr14254]

Hi David, really is looking a very nice job.

Regards Nick.

[Brian HParticipant @brianh50089]

Thanks for sharing that David, I'm sure it will help one or two of us the consider what looks at first sight, rather tricky jobs and your workmanship is excellent.

Brian

[David George 1Participant @davidgeorge1]

Made a new top cover for gear casing.

David

 

Edited By David George 1 on 03/04/2019 19:53:10

[David George 1Participant @davidgeorge1]

Pinned the casting to the shaft.

David

[geoff walker 1Participant @geoffwalker1]

Looks finished now David, except for the painting.

Assume the gears are ok, whole job very professional.

I used the grub screw method to hold it together while fitting the taper pin, GMTA?

Completed mine about 9 years ago, same patterns used for the castings as yours.

Here is an archive picture.

Geoff

[David George 1Participant @davidgeorge1]

Finished and painted Tumbler reverse. It works very well but need to play around with gearing for fine feed.

David

[geoff walker 1Participant @geoffwalker1]

…….and here is another recently made tumbler reverse for a myford M type.

Complete with acetal (delron) gears.

No two cast iron gears mesh in the fine feed set up shown (214 t.p.i.)

The drive is very smooth and very quiet.

Very impressed with the physical and practical properties of acetal, easy to machine but very tough and in my opinion entirely suitable for replacement gears on a lathe of this size.

This tumbler is here to stay!!!

Geoff

[Dave WoottonParticipant @davewootton]

Excellent work and posts well done David and Geoff, a very worthwhile addition, nice to see these older machines in action. One of my future ambitions is to restore an M type and carry out some of the modifications I've seen over the years. I've used one and was very impressed with it, although I struggled with the reverse carriage feed, but this would be one of the modifications that I'd like to do anyway. I should stop pretending to be a model engineer and just admit I like tinkering with old machines!

Dave

Re Delrin gears I bought some for my Bantam 2000 from a chap on ebay, transformed the machine from horrible ringing steel gears to (almost) silence.

Edited By Dave Wootton on 10/07/2023 12:43:33

[BazyleParticipant @bazyle]

Odd coincidence that I was cleaning my knob at the weekend and was a bit jealous that yours appeared to be brass but it is just the lighting. Mine (Myford post war) has a flatter mushroom though.

[David George 1Participant @davidgeorge1]

Hi Bazyle my knob is brass. I just thought a brass knob would look well instead of cast iron on the drawing and it pollished up easily with a quick rub ocasionaly. I also adjusted the shape to suit my whim.

David

[David George 1Participant @davidgeorge1]

Hi Bazyle my knob is brass. I just thought a brass knob would look well instead of cast iron on the drawing and it pollished up easily with a quick rub ocasionaly. I also adjusted the shape to suit my whim.

David

[David George 1Participant @davidgeorge1]

Being on a network I don't usually use which is very slow, clicked the button too many times, sorry about duplicate posts

David

Edited By David George 1 on 10/07/2023 20:49:53

Edited By David George 1 on 10/07/2023 20:50:50

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