[AMCjeepCJ]

Hi,

I cut A2 and D2 by the ton up to and over 62 rockwell. If you need to remove a lot of stock in a hurry, you can't go wrong with round insert ceramics. I have a 40 taper VMC similar to yours and it cuts great minus the insanely hot chips that are prone to catching things on fire. The finish with ceramics using negative rake is almost to the point of a mirror. You can definitely see yourself very clearly in the reflection when things are running smoothly. Another nice thing about negative rake cutters is that the tool pressure is EXTREMELY low since you are basically not cutting material but rather wiping away melted metal much like a windshield wiper on a car~

Hope this helps although I realize you are probably doing detail work instead of general machining. My experience with other operations besides facing I normally run heavy feed, slow RPM and flood using HSS roughers. Right ATM I'm running 500rpm .500" DOC full width on a .750" 4 flute rougher at I think off the top of my head was 1.6 IPM. I'm pretty sure that is accurate and I have not broken a cutter in approximately 30 parts with 25 left to go.

Each piece gets around 36 grooves cut in the perimeter 1.000" deep and I've had no problems with cutter breakage since I have slowed everything down and increased the feed with the HSS cutters. I'm sure there are better methods to do it but this works and I had a pile of those cutters lying around to use verses buying new tooling.

BTW, on my 2 inch cutter I run 1900 rpm and something like 30-50 IPM or more at roughly .025-.05 DOC. I've experimented with (accidentally) over .125" DOC and it worked just as good but I'm not really brave enough or in a big enough hurry to do that very often, although after doing it by accident, I tried it on purpose and it worked but I was nervous and it increased the tool pressure to the point my fixture started to move but the cutters did not break. Besides, I don't think a 40 taper machine is probably the right piece of equipment for that kind of thing.

I bought indexable carbide counterbores and at the recommended speeds I have not actually EVER changed the inserts and there is no noticeable wear after counter boring hundreds of inches of holes in both A2 and D2. The only reason I have not changed the inserts is because the screws fused themselves into the cutter body and since the cutter has paid for itself several times over, now I'm just curious how long it will actually last before it explodes~

Please post your feeds, speeds, DOC, stepover %, etc. so we know what you had success with~

Later taters,

C