01-04-2015, 02:47 PM
Actually Jack, there's not one insert I know of that would work great in aluminum AND steels for one major reason. Aluminum needs a sharp edge and usually a polished or low-temp applied coating to retain the sharp edge. Steel needs a honed edge.
That said, Walter USA recently came out with a grade that is truly "universal" and works at virtually all speeds in all materials. That grade is WMP20S. It is a CVD aluminum oxide coating, thickest on the market. I'm switching to this for my home shop as I expend the current stock. Yes, you can use it in aluminum with no problems other than its chipbreakers just won't work in aluminum, few really do. I have these inserts in a CNMG432-NM4 WMP20S for roughing/medium machining and in CNMG431-NF4 for finishing. I haven't even indexed the insert in weeks, though I'm not in there every day. I did use a different geometry, uncoated old insert for turning the bronze bushings I made yesterday, but only because I'm trying to use them up and this was a good excuse.
That said, Walter USA recently came out with a grade that is truly "universal" and works at virtually all speeds in all materials. That grade is WMP20S. It is a CVD aluminum oxide coating, thickest on the market. I'm switching to this for my home shop as I expend the current stock. Yes, you can use it in aluminum with no problems other than its chipbreakers just won't work in aluminum, few really do. I have these inserts in a CNMG432-NM4 WMP20S for roughing/medium machining and in CNMG431-NF4 for finishing. I haven't even indexed the insert in weeks, though I'm not in there every day. I did use a different geometry, uncoated old insert for turning the bronze bushings I made yesterday, but only because I'm trying to use them up and this was a good excuse.