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Half Nut material


Nov 29, 2022
La Motte, Iowa
I made a new lead screw for my lathe. Bought acme threaded rod from McMaster and did the rest myself. It turned out really nice. Now I'm getting ready to make some new half nuts. My question is how bad or good idea would it be to make them from 6061 aluminum. I can run several sets easily if they wear out fast and they are easy to change. My goal is to preserve the lead screw. Does 6061 have any abrasive qualities? Any enlightenment would be appreciated.

Not a great plan I think. If anything aluminum would load up with grit and act like a lap. I also just think it wouldn't work well as a half nut

With a bit of cleaning an iron or bronze nut and the lead screw will last decades. You could go with low friction plastic like Igus but that is all over complicated.

Aluminum has a tendency to gall against steel and essentially weld to steel under even moderate friction loads. Also steel and aluminum corrode each other.

Brass, bronze, cast iron, even a different hardness of steel are all much better choices.

I would consider UHMW or Delrin plastics as far superior to aluminum in that application as it's much easier to machine, won't wear your lead screw and the cost is not too bad especially if you can get remnants. Plus more forgiving if everything doesn't line up exactly.
Thanks for the advise fellas. I can definitely see chips getting stuck to the aluminum. Not good. Guess it's material shopping time.
Also Moglice works good too. You bore out the old nut threads and roughen the bore , if there is room cut a couple of keyway in it. Drill a hole in the bottom and top. Spray the screw with wax release agent, insert a plastic tube in the bottom and a chimney tube in the top. Install and align the nut close to the front of the cross slide. Seal the ends of nut with putty or clay, Them mix the 2 part epoxy Moglice and squirt it in the bottom until goes up the chimney tube, pinch the bottom tube with visegrip and let it dry. Check out Moglice.com
I like all you guys ideas. I got some free machining brass and I'm gonna hog a set out of that. That brass should be easy on the screw I would think.
I like all you guys ideas. I got some free machining brass and I'm gonna hog a set out of that. That brass should be easy on the screw I would think.
Honestly, if you are going to go through the trouble of making your own, Bronze is likely better than Brass. Free cutting metals machine great, but may not be as suitable for the loads and frictional demands as well. Buying a premade nut and modifying it to your needs seems like the wisest choice to me.

I’m not a 3d printer guy but maybe printing some?
You can get professionally sintered nylon 3D prints, but a split half nut is a very tricky part as far as loads and engagement are concerned. A home printed unit certainly wouldn't last or be the right material, and a professional one in nylon is still questionable and at a high enough cost that a known solution like the pre-fabricated nuts suggested above seem like a better choice. Someday we'll likely be able to effectively print metal at home though... just not today.