View Full Version : Speeds and Feeds for countersinks

11-21-2007, 01:35 PM
Anybody know of a chart or formula for determining the speeds and feeds for countersinks?

11-21-2007, 01:48 PM
I just used 10 ipm with 500rpm on a 1/2 od cutter, it worked well.

11-21-2007, 02:03 PM
A lot depends on how you are using it. Such as manual with no coolant or on a cnc with flood coolant. But as far as sfm, you can take the hole diameter you are putting the countersink into as a starting point. In other words, if you are countersinking a 1/2 inch hole, then calculate the sfm for the material you are cutting based on the 1/2 inch hole. Remember that the outer diameter of the countersink is cutting at a higher sfm than the inner part. So if you are cutting a real large countersink onto a part, you might want to calculate the sfm for the larger diameter of the countersunk hole, and use that for your running rpm. As far as feed goes, I'd go with .002 to .006 per flute per rev depending on the type of material and the finish I'm looking for. I know this isn't real clear but I thought I'd take a shot at it.

11-21-2007, 02:36 PM
This is on a VMC with flood coolant. One concern I have is chips getting in the way. Would a peck feed cycle be better?

11-22-2007, 09:45 AM
That got me close, still had to back it down a little. I'm use to the bridgeport and its a whole different world. I still wish I could find a chart though.

Thanks again

11-22-2007, 09:57 AM
Glad that helped Mike. I run several Mazaks VMC and a couple of horizontals and I never peck with a countersink even when going to the outer diameter of the cutter. Most of the time I just goes with what looks right and the type of metal plays a big role in the speed. We cut a lot of stainless and hastelloy so if you don't pay close attention to the speed when setting up the machine, the tool won't last past a couple of holes.

I looked on the M.A. Ford website and found this chart.
You still need to take into consideration the largest diameter that the countersink will be cutting and use that for a starting point. Plus, it's been my experience with a lot of these charts that most seem to be a little fast if your looking for maximum tool life.

11-22-2007, 10:26 AM
Thanks Jonathan, Thats just what I needed.