- Joined
- Jul 29, 2014
- Messages
- 2,848
Ha ha, here I am giving advice on the internet. Well, with the 71 blade and GTN-3 insert, I feed in firmly enough to get a chip started...otherwise you're sunk and the insert just rubs. The chip will come off and start to curl up, if the RPM is too low, the chip will come off too straight and won't break soon enough. I like the chip to form a pretty tight ball...and the edges of the chip, formed by the dished out portion of the insert, will curl inward, clearing the sides, especially important on deeper cuts. As the ball forms, it should break off in a timely way, and if not breaking soon enough for you, just slow the feed rate a bit and it will come off almost instantly. If the feed force gets a bit harder to get the right chip formation, it's time to pause and increase RPM. The feed pressure should stay about constant, and If the speed is correct, the chips will look about the same, all the way to completing the cut. And if your tool is not right on center, that last little thread is going to take a lot of feed pressure and bad things can happen. Best to check tool height accurately before starting.
And that's about all I know about that.