The Rivett 608 lathe has knurled screws to lock the micrometer dials. These are quite long, going down the centre of the feedscrew and pushing out a radial wedge.
I am making some new feedscrews and have realised that these screws are threaded 0.190" x 30 This is probably #10-30 though 3/16 is possible. However I have never found a screw to be _above_ nominal diameter, so think it is #10-30. #10-30 is listed as an old ASME (pre-war) standard. But finding the taps in the UK seems about as easy as you would expect. So, how else to cut the thread? Maybe a very tiny thread mill? Single-point cutting might work, but it's a rather deep thread for the diameter. And I don't have a suitable tool (such as https://www.ebay.com/itm/383646508366 ). Thread-milling would be an excuse to add live tooling to the lathe, and an almost-suitable cutter is affordable: https://www.shop-apt.co.uk/single-tooth-thread-mills-for-general-use-internal-60-partial-profile/internal-partial-profile-60-thread-mill-05-08mm-pitch.html -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
