Machining a tool steel point for a vintage 16 oz plumb bob was the first time here but it worked out in the end after a few stumbles. Here again a special size thread and I use an old trick or two to get it done and a very nice tool restored.
This Monarch 10ee has lead screw reverse that would make cutting this .195 " x 32 thread at higher speeds but I elected to use the threading dial at 500 rpms, about as fast as I can do it at that pitch. The results are very good but I use the lead screw reverse most always on the finer pitch threads to avoid the small errors from camming in the half nuts to get the 10ee fit. Leaving the half nuts engaged on the heavy gear head lathe for very fine pitch threads offers much more control.
I feed in the tool at 29.5 degrees, the last pass is often feed straight in around .002" to shave the right flank and produce a professional thread that is consistent and under control, I always make a chip with a deadly sharp tool, no Atlas bench lathe spring passes. Watch the crest of the thread, with some practice the eye can detect .002".
I will flame harden this part from 01 drill rod when I can get some more Acetylene.
21 ноя 2023
