I posted this elsewhere but here probably makes the most sense.
The crossfeed on my lathe, a 1943 Monarch 12ck, had about 0.090" lash so I set about making a new lead screw and nut. It was challenging. The screw was 7/8-4LH acme with an OAL of 24". This resulted in me making some material compromises from the 41xx screw and bronze nut to an 1144SP screw and Delrin nut. After some pencil fiddlin, I determined Delrin was up to the task and set forth.
Step one was to turn a tap, the first one I've ever made. It didn't work as well as an OSG, but it measured right and cut some threads. Much relief was added after I took this pic.
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Step two was to create the nut. Straight forward mill work there.
Step three was the screw. With planned cuts I was able to keep my TIR and taper very low over the shaft's lengths and diameters. The screw measures about 0.001"/1" lead error. Certainly not factory quality, but I'll take it.
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I didn't get any pics of the cutting in action, I was pretty concentrated on not botching the job. Heres the screw and nut together on the plate, and then again as they're loaded into the taper attachment slide's bearing block.
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I learned a lot in this project...like how to turn your mill into a tool grinder.
Monarch wanted $1600 (5years ago) for this screw/nut combo, and while there's would have been better I dont think they'd be justifiably better than my $50 effort.