Bronze Cross feed nut....ain't eating !!

[rafe]

I knew this was coming ,sort of.... there was a lot of slop when I first got it. I did some threading yesterday and it seemed to be getting worse ....today it gave up. I disassembled it and the feed nut has very little thread left.(shot) The feed screw is showing some wear too. I measured a first thread that has seen little if any wear it's
.067" in the middle where wear is most severe .047" I could most likely live with that but I think I'd rather do it right....seems like some play in the thrust bearing too.
Can someone or more offer me advice on this. it's a 14 1/2 " South Bend. I could mate some acme threaded rod (8tpi) to the shaft, get the new part, make a new part but all I have is my 6"atlas....The bronze bushing needs new or sleeving? Any way all feedback is appreciated and helpful ...Thanks in advance and regards R

 

[george wilson]

Wouldn't the cross feed thread have to be left hand?

 

[Richard King]

If the factory price is to high. Check with Green Bay Mfg. They sell stock Acme screws and bronze nuts. You have to machine to fit. More later...I'm to on cell...I have hate it...Rich

 

[fastback]

I remember a while back that Jeff over at Tool4cheap was selling some cross feed nuts for Southbend lathes for around $35.00 (I think). You may want to give him a call.

 

[12bolts]

rafe,
This thread has the basics http://www.hobby-machinist.com/show...ss-slide-lead-screw-nut?highlight=acetal+feed
but if you google acetal feed nut a few other sites will also come up with some threads. There is one excellent thread by a poster "matt"?? i think??
Cant find it at the mo. He runs through the whole process from go to whoa. Very informative and lots of pics.

Cheers Phil

 

[davidh]

rafe,
This thread has the basics http://www.hobby-machinist.com/show...ss-slide-lead-screw-nut?highlight=acetal+feed
but if you google acetal feed nut a few other sites will also come up with some threads. There is one excellent thread by a poster "matt"?? i think??
Cant find it at the mo. He runs through the whole process from go to whoa. Very informative and lots of pics.

Cheers Phil

Evan (Williams) on the other site I believe

 

[iron man]

I dont know if this helps but brass taps really easy so I made my own left hand tap for my lathe out of drill rod it looks crude but it will tap through a 2" long piece of brass like it is nothing. I have also taken a piece of pre-made threaded rod harded it with a hardening powder cut some grooves in it for relief and used that as a tap it leaves a very nice tight thread. If your screw is 10 tpi I can thread a piece for you.. Ray

 

[rafe]

So ....at this point I'm thinking of getting a foot (min. they will sell) of acetal rod and forming a new nut on a couple of feet of 3/4-8 lh acme threaded rod ... I think I have 11/16" now I don't know if that would be an issue ....and getting this fixed myself ...I'm thinking I could cut off the worn threaded rod and join (fit) the fresh piece of acme ....otherwise I'm looking at over $300 in parts which I dont have. the hard part is the 6" lathe may not be up to the task, but I think I can put the SB back together and use the compound for turning the threaded shaft of course I wont need it to drill the other piece (tailstock)......or I could just buy a bronze nut and put up with the backlash .....that would be quicker...i'll sleep on it OR I can drop from 11/16 down to 5/8" (which some of them were) and get the nut and threaded rod for around $80 and get it up and running, that's most likely the way to go ?? tools for cheap $58 (do-able)....the smaller SB's are less

 

[george wilson]

MSC sells left hand acme threaded 1/2" x 10 tpi rod. It comes in different levels of precision. The real precise rod gets expensive. You only move the cross slide a small amount when finish turning a shaft to an accurate diameter,so I doubt you need real precision rod.

For the feed screw of a milling machine's table,it would be different. You might move the table a considerable number of inches to accurately drill holes.

They also sell steel nuts for the rod. Steel isn't the best answer,but for a home shop,I don't think you'd wear out the threads any time soon. Keep it oiled. The RPM on the cross slide is never anywhere near fast. It is the best way to get by cheap.

 

[rafe]

rafe,
This thread has the basics http://www.hobby-machinist.com/show...ss-slide-lead-screw-nut?highlight=acetal+feed
but if you google acetal feed nut a few other sites will also come up with some threads. There is one excellent thread by a poster "matt"?? i think??
Cant find it at the mo. He runs through the whole process from go to whoa. Very informative and lots of pics.

Cheers Phil

Great thread on PM I think it was his name was Evan...maybe that's the one you saw? Anyway I may go that route if not this time at a later date Thanks