I'm looking for advice from anyone who's got previous experience with Onsrud's Max Life compression spiral bits -- specifically bit # 60-163MW. This is the first time I've used this particular bit and I am attempting to cut through 1/2" MDO (also a first for me) in a single pass (it's a 1/2" bit). According to Onsrud's "Soft Plywood Cutting Data Recommendations" (2023 version), I should be calculating feeds and speeds using a chip load in the .021-.023 range.

Using a feed rate of 3ips and .022 chip load, the chip load calculator indicates 4091 rpm's for my spindle. This is significantly less rpm's than I use with all of my other bits, so worried, I did a small test cut and was surprised that it seemed to work fine. However, once I started cutting the full file, it was instantly clear that something is way off. The spindle never stalled, but it was acting like I was trying to cut with the spindle turned off and I quickly lost position.

I did some experimenting and was able to run the first of several files using .012 chip load, 3ips, 7500rpm, but I am still hearing things that sound like moaning during the cutting process.

At this point, I am just guessing what my settings should be and would like to hear from anyone who's got some experience with this bit cutting MDO.

Thanks!!