Lathe Compound Feed Nut

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PeterT

Ultra Member
Premium Member
thestelster said:
Now to start figuring out how to make a telescoping cross-feed screw and associated parts for my taper turning attachment.
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Way to go. Looking forward to what you come up with. This (telescoping) topic got discussed a few times on the forum so maybe do a search. Maybe 3-4 years ago now? Anyways I recall someone posted some excerpts from parts manual that showed the components reasonably clearly.

To put another dangerous thought in your mind, you might be able to integrate a profile follower where you attach a 2D template of some shape & the carriage tracks it. The options would be endless. No more ball turners! The big boy lathes use hydraulics to apply follower feed pressure but I wonder if this could be dumbed down a bit? Keith Fenner recently posted a video showing the hydraulic follower in action to give you a sense.
 
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thestelster

thestelster

Ultra Member
Premium Member
PeterT said:
Way to go. Looking forward to what you come up with. This (telescoping) topic got discussed a few times on the forum so maybe do a search. Maybe 3-4 years ago now? Anyways I recall someone posted some excerpts from parts manual that showed the components reasonably clearly.

To put another dangerous thought in your mind, you might be able to integrate a profile follower where you attach a 2D template of some shape & the carriage tracks it. The options would be endless. No more ball turners! The big boy lathes use hydraulics to apply follower feed pressure but I wonder if this could be dumbed down a bit? Keith Fenner recently posted a video showing the hydraulic follweer in action to give you a sense.
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Thanks Peter. @Brent H posted some links and I printed off some prints, but I'm not quite adept at comprehending 2-D drawings. I'm more of a touchy feely kind of guy.

And no...I do not have plans for making a copying mechanism.....but never say never!!
 
Danzo187

Danzo187

Member
Premium Member
thestelster said:
Lathe: Standard Modern Utilathe 1654

I decided that I want to address the slop that is in the compound feed mechanism. And, yes, I'm currently using a solid tool post setup, so what better time than now to fix the problem.

I have 0.020" backlash. Taking apart the compound, it looks like it has been worked on before. I think the original crossfeed nut was integral with the base of the compound. It looks like it was replaced with a fabricated unit from cold rolled steel, and attached by a screw from the bottom. The threads of the feed screw, 1/2"-10RH acme, are, I think, acceptable. I measured the threads in 4 different places with the 3-wire method, and the pitch diameters were consistent within 0.0015", of each other.

So I will only make a replacement nut from C95400 aluminum bronze. And I will use a tandem tap to do the threads.
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I too had .025 compound backlash on my SM 13 inch 2000 series ,when I made a new brass feed nut I made the boss so it was .001 press fit maybe as much as .0015 pressed it in and backlash is now and has been for a few months .003 , I found that both compound and crossfeed nuts excessive play just gives a ton of backlash ,for my crossfeed nut I made it just like the original then ground a spacer for distance between the top of the nut and the bottm of the crossslide....again .003 backlash ,rigidity will do the trick
 
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