[Stuff-Builder]

Hey all,

I'm running a Taig 2019CR with flood coolant, and I'm trying to do some slotting, pocketing, etc with 1/4" endmills in CRS/HRS. Haven't had much success so far. I tried both 2600 RPM and 1650 RPM, at around 3-4 in/min feed rate. Depth of cut was (supposed to be) .125 per pass. This was with a 2 flute center-cutting carbide cutter. The cutter seemed to be digging in to the material. I eventually chipped the cutter and everything stalled out.

I want to try a smaller depth of cut - maybe .050" per pass. I have a 3-flute HSS cutter that I can try too, but it's getting a bit long of tooth.

My reference book says SFM should be about 75 for the HSS cutter, or around 200 for carbide. Using my two gear options, I could get either 108 or 170. It recommends a chip load of about .001", so using the above SFM options using my 3-flute cutter, that gives me a feed rate of 5 in/min @ 1650 or 8 in/min @ 2600.

What sounds like the right range? I'm thinking of running up a test piece with several lines at different RPM and feed rate. Once I find a combination I like I can play with the depth of cut.

Also, any idea where to buy HSS cutters with 1/4" shanks? Everything from Enco in that size is solid carbide.

Thanks, Scott

[Robin Hewitt]

The cutter seemed to be digging in to the material. I eventually chipped the cutter and everything stalled out.

Sounds like the sideways force from the cutter is bending the machine. Does it cut on an angle and the straighten out when you lift at the end so your slot looks more like a tick?

If so, and you don't have to cut lots of these slots I suggest you halve the cut depth.

Obviously less overhang anywhere is desirable, if the machine is more rigid in the other axis, turning the job through 90 degrees might help