Thread: Making a Rolling block rifle on my lathe.

Originally Posted by homebrew.357

My top slide has a bit of slop in it to, trying to think how you cut a acme thread to makeup a new worm nut. Always try a mill with the cutting force downwards and my lathe is always covered in swarf, cooling fluid, cutting oil and T68 lude oil, also some gun drilling oil when I get a leak at 400psi, the celling's not rusty ether. The lathe is sitting on carpet, in a steel tray, don`t want to stuff up the carpet.

You will have to grind up a piece of HSS to the Acme thread shape (taking the dimensions off your top slide screw) making sure the depth of the tool will allow enough depth of cut. Make sure the tool is a few thou narrower than the crest of the screw thread. Because the Acme thread is tapered equally on both sides it is just a question of making cuts until your screw shaft is a snug fit. This will leave a small recess in the crest of the thread for crap to accumulate. You could lap the thread with the screw shaft and some Brasso for a perfect fit. When assembled adjust the gib strip to give a fairly firm fit which will help prevent sudden movement of the slide.