12 * 12mm MGEHR1212-3 Lathe Cut-Off Grooving Parting Tool Holder with 10pcs MGMN300 Inserts

The holder itself is probably okay, but the inserts are absolute garbage. I've never seen carbide inserts turn into an oily paste in the process of trying to part a piece off. They would cut fine for the first .010-.020 and then stop cutting. I withdrew the tool, cleaned it off, oiled it and tried to contionue cutting. What I got wasn't chips, but a dark oily paste. Upon examining the insert I observed that it had worn away to the point of the chip breaker (about 1/16 to3/32) leaving a polished surface on the tip of the insert. I was trying to part mild steel and there is no way mild steel should be able to do that to a carbide insert. I've had carbide chip and fracture, but never had it turn to powder before. I went back to the old standard HSS parting blade and have had no issues using that to part the same steel. The tool holder itself seemed well made and held the insert well.