Switched bits and now I'm burning wood

Woah boy, it’s been a process!

I finally got some good cuts going and was very pleased.

I was doing some test cuts to see if I could reduce machining time on the larger parts I had in mind, and broke my 2-flute straight cut bit. No problem, I knew it would happen at some point and I was pushing it. There’s a CNC specialist about a half hour drive away so I went and got a 5 pack of single flutes.

I whacked this in, dialled the speed and RPM back a bit, and fired her up, only to be greeted with some lovely smoke!

In playing around with it, the single flute seems to be just packing its slot full of chips. If I put the DOC to 2mm and chase the cut around with the vac to manually clear the debris I can get some decent stuff but it’s still charring. CNC shop suggested faster feedrate, which caused the stepper to start slipping on the belt.

I was hoping to get some larger parts done before the weekend, but it looks like that won’t happen.

The leftmost vertical line shows what I’m dealing with. DOC was 3mm, at 8mm/s spindle roughly 15k. The first pass was fine, but as it came back for the second pass it jammed up against the debris and started to slip on the belt and char.

The piece on the right was cut with the 2 flute, at 3mm DOC, 12mm/s and spindle at roughly 30k. The piece I’m holding was cut with the single flute, took twice as long and I had to manually clear the slot, and even still charred. 2mm, 8mm/s, 15k.

Can we get some pics of the endmills?

This is the new one. I thought I’d taken a picture of the borked one, but seems I didn’t.
New/current: GL3.17
Old one 3.175 x 3.175 x 22 mm (Probably going to order a couple of these and a spiral upcut from this guy, express to hope for it by the weekend)

Funnily enough, the page for the new one (where I’m having debris problems) specially says it’s good for debris removal, and the page for the one that seemed to leave none, specifically talks about how it leaves a lot!

I think that you will have better luck with upcuts for removing packed chips.


Yea, those don’t work too well without air assist. Spiral endmills work better.