- Joined
- Apr 24, 2021
- Messages
- 462
I bought some cheap carbide insert threading tools from Amazon with 5/8 shank. I was trying to thread 5/8 4140 stock with 18 tpi. I had 2.5 inches of stick out. I was going to use my live center, but decided not to because I couldn’t fit the tool with it. I took a scratch pass then proceeded with .005 doc. Everything was good until I hit .040 deep out of the .067 I needed to cut to hit minor diameter. The tip of the tool broke off, but I continued because the thread looked ok and it was the very bottom of the tool.When I hit .050 it snapped even more, but very jagged, but I’m pretty sure the thread was ruined at .045 before the insert broke the second time. I was running 400 rpm by the way. My compound was set to 29deg with my qctp turned so it was at zero degrees. I advanced my depth with compound.
My question is, why didn’t this work? Was it too much stick out without support? Was it speed? Was it my process? Or I did everything wrong?
My question is, why didn’t this work? Was it too much stick out without support? Was it speed? Was it my process? Or I did everything wrong?