edwin dirnbeck
Hot Rolled
- Joined
- Oct 24, 2013
- Location
- st,louis mo
Since 1976 ,I have made thousands of DIFFERENT parts on NC lathes in tool and die shops.Most parts are nasty tool steel,prehard 4140,h13 d2 ect.Not production quantities ,usually 1 to 10 parts.. I found that damage to the parting tool usually happens when the part comes free and the part goes flying.SOO,I allways program the parting tool to rapid retract when it reaches .150 diameter.The lathe stops and the part is left hanging. I can wiggle the part back and forth and it breaks off.For long parts ,I increase the diameter. If I miscalculate and the part wont break off easily, a few strokes with a good hacksaw ,weekens the nub and the part break off. OH YEA,this also keeps the part from getting banged up when it goes flying.This also works when faceing.The hardest thing on carbide is cutting on center. You have almost zero surface feet per minute and you are bulldozing the nub at center.If you leave the nub,you can easily remove it and make a beautiful part with a 2 inch air sander with the spindle turning about 300 rpm. Of course this means reaching in and running the spindle with the door open. Edwin Dirnbeck