Broken nibbler punch

Date 02-03-2009 03:22

I have a metabo nibbler less than a year old and I just broke the punch cutting some 16 ga. 304 SS sheet. The tool is rated for this thickness of SS, but the punch should not have broken this soon. It's on it's way back to the company, hopefully they will replace the punch, as my local dealer wants 75 bucks for a new one. The question I have for all of you skilled and experienced metal workers is this: Would using a sulphured cutting oil some how be detrimental to the punch? I know sulphur is added to steel to make it free machining, same with the cutting oil, but I seem to remember something about sulphur and tool steels. Anyone shed some light?

By DaveBoyer (*****)

Date 02-03-2009 05:00

I have used a lot of sulpher cutting oil machining parts, I doubt that is Your problem.

Where did the punch break & what did the punch look like where it broke?

How does the die look?

By Tommyjoking (****)

Date 02-03-2009 09:59

I agree with Dave, the oil was not the culprit....the heat treat/parent material well......

By devo

Date 02-06-2009 13:52

The punch broke along the cutting edge, destroying nearly the entire cutting edge. It ws a jagged break, at it's worst it broke off about .25" of the punch material. The die looks alright, but there was enough metal left on the punch to regrind it. So after some careful and cool regrinding, I took a trial cut, and some sheet metal immediately welded itself onto the side of the punch. It cut well enough, but after a 10" cut, the cutting head was getting mighty hot. But it's still under warranty, so hopefully it will be fixed soon.