Which material?

[ltlvt]

I'm getting ready to start making the new lead screw and nut for my cross slide on my Clausing 5913. I've bought a length of left hand acme threaded rod and it is 4140. So the material for the lead screw is already selected. My question is the nut. The original nut is some kind of brass allow. It did wear the original lead screw in the high usage area of the screw. The nut also has some wear so I will replace both at the same time.

At the moment I am considering making the nut from Cast iron or from a piece of unknown bronze like material that I think may be Ampco. (hard to scratch) I will be tapping it with a Acme Tap. I have made one for my other lathe out of cast iron and tapped it and was not an easy job of tapping but did turn out well. I did a test tap on the Bronze like material with a 5/16-18 trap and it seems to tap pretty easily.

So I am asking for opinions of which to use. The machine will be used for Hobby turning and never be used commercially. I don't remember for sure but I think the thread is 5/8-10 acme left hand. Thanks in advance.

 

[mksj]

Most that I have seen are bronze, characteristics are described below. Aluminum bronze variants tends to have high wear resistance.

Acme Screw Products - Complete Assemblies

Contact Nook Industries if you’re looking for precision acme screws and lead screws. We provide precision inch acme screw and metric acme screw products.

www.nookindustries.com

 

[cathead]

I would venture to say that either one would work fine. If the bronze taps easier, I would start with that.
If lubed regularly, it will last a long time, even if it isn't the best alloy out there.

 

[C-Bag]

I’ve been wanting to do like UlmaDoc did when he replaced the nut on his lathe and used Delrin. Says it’s smooth and is wearing beautifully.

 

[ltlvt]

I’ve been wanting to do like UlmaDoc did when he replaced the nut on his lathe and used Delrin. Says it’s smooth and is wearing beautifully.

I'm lousy at turning Delrin. I want it to behave like steal when I machine it and it doesn't. It doesn't seem predictable either. It's because I am lousy at machining it. LOL

I intend to save the old nut because I have another Moglice job on my Clausing 100 lathe to do. There should be enough Moglice left over to refill the old nut and re-machine and tap it for a test. It seems to be an excellent bearing surface and cures Glass Hard. After all I am a Hobbyist and the test will improve my skills.

As it stands now I am leaning towards the cast iron since it is easier to turn a square shape to a Tee-nut than the Ampco will be to turn from a round shape to a Tee-Nut. Like I said I am a Hobbyist, and the work will be a pleasure.

 

[ltlvt]

I went ahead and sawed out the blank from cast iron this morning. I will square it up on the mill then saw out the bulk and then turn the stem in the 4 jaw. Then back to the mill to bore the cross hole and tap. I am considering turning a plug out of the Ampco and doing a patch job in the old Tee Nut just for the fun of it. We will see the best or both worlds.

 

[verbotenwhisky]

I'm getting ready to start making the new lead screw and nut for my cross slide on my Clausing 5913. I've bought a length of left hand acme threaded rod and it is 4140. So the material for the lead screw is already selected. My question is the nut. The original nut is some kind of brass allow. It did wear the original lead screw in the high usage area of the screw. The nut also has some wear so I will replace both at the same time.

At the moment I am considering making the nut from Cast iron or from a piece of unknown bronze like material that I think may be Ampco. (hard to scratch) I will be tapping it with a Acme Tap. I have made one for my other lathe out of cast iron and tapped it and was not an easy job of tapping but did turn out well. I did a test tap on the Bronze like material with a 5/16-18 trap and it seems to tap pretty easily.

So I am asking for opinions of which to use. The machine will be used for Hobby turning and never be used commercially. I don't remember for sure but I think the thread is 5/8-10 acme left hand. Thanks in advance.

I have made a couple of these for mills and I always use brass because that is where I want the wear to be, not in the screw...

 

[benmychree]

I made a cast iron cross feed nut for an old American High Duty lathe, I don't remember if it was 4 or 5 tpi, but I single pointed them both, they came out with only about .003" backlash and lasted many years without appreciable wear, Ampco would be my last choice, it would be difficult to tap and invite breakage of the tap.

 

[ltlvt]

I made a cast iron cross feed nut for an old American High Duty lathe, I don't remember if it was 4 or 5 tpi, but I single pointed them both, they came out with only about .003" backlash and lasted many years without appreciable wear, Ampco would be my last choice, it would be difficult to tap and invite breakage of the tap.

I like the idea of using cast iron also. I used it to make the nut for my cross slide on the Model 100 Clausing. Cast iron was what they used from the factory then. The screw was not worn as much as the one on the 5913 that has the bronze alloy nut. Also when you think of it Cast iron is the material used for the half nuts on all the lathes I have ever used.

 

[benmychree]

Yes, cast iron half nuts and cross slide nuts are the norm unless you are talking cheap pot metal machines.