Spare Parts #4 - Making, Hardening And Tempering A Form Tool For The Lathe
Added 2015-09-04 23:38:22 +0000 UTC
Comments
Hi John, lovely to hear from you! The relief angle for that part of the cutting edge is partly generated by the angled hole, but it needs an extra component to make it correct around the whole edge. The hole on its own gives exactly correct geometry at the very back of the curve, but becomes progressively "less correct" as you move closer to the front. Until at the 2 front corners, the relief is exactly zero. You can get a good look at how it needs to be at the 28 second mark. To be honest its not overly critical for brass, and in the past I have skipped this extra effort and just run with the angled hole. On small cuts it works just fine. But for the rope knurl I'm making at the moment, the cutting edge is at the upper limit of what my little lathe can cope with, so this time it all needs to be spot on. Thanks for asking mate :)
Clickspring
2015-09-05 19:24:46 +0000 UTCHi Chris, If you drilled the central curve at 10 degrees, why do you still have to file it out? Shouldn't it already have enough clearance because your drilled it at an angle? I can't wait to see how this knurling works. It looks really elegant.
John Creasey
2015-09-05 11:48:25 +0000 UTC
