Posted: Thursday, July 19, 2018 3:58 AM Quote
My recently rebuilt SB 9 machine well with small diameter (< .5") diameter scrap aluminum bar stock. I can do brass quite well too, both leaving pretty much good finishes. But scrap steel from.3" to 1.0" in diameter never leaves a good finish. It horribly rough, bad enough where little shavings are hanging off it. It is MUCH harder to move the bit through the steel. RPM, feed rate, depth of cut combinations have no effect on finish. I know little about tool grinding but my efforts did seem to improve results on aluminum and brass.
I wondered if one known issue is contributing to the finish problem. The 3 jaw chuck i have is worn out. The clamping face of the jaws are not even, as you can see daylight in places when clamped, with most if it apparent at the front of the jaws. Could this be the problem, or maybe the unknown makeup of the steel I have? Even with compound turned parallel to the spindle, and carriage locked, the finish is still unbelievably awful. The sound is also loud and screeching even with oil.

Please help.

I didn't find the right solution from the Internet.

References:-
https://bit.ly/2uz1mrM
Great Explainer Videos

Thanks!