I was originally very disappointed with its performance
So I built a very cheap and loose CNC machine using a RotoZip as a router. I was originally very disappointed with its performance. After swapping the spiral cutting bit made for the RotoZip with one of these HQMaster router bits, I feel much, much better. The old RZ cutting bit could not run properly even at 100 mm/min with a layer depth of just half a millimeter. My CNC uses small NEMA 17 86 oz/in motors with 5/16 18 tpi threaded rod for the axes (yes, cheap build). It was hard for the motors to push the bit even at this slow speed and very low cutting depth and it skipped lots of steps. When I tried this HQMaster bit I got it to go at 300 mm/min with a layer depth of 2 mm and it was like going through butter (in 19 mm pine board), without the X/Y motors skipping. It can probably do even better (faster and larger layer depth) but that's as far as I've pushed it this evening. Still, it's way, way ahead of the normal RotoZip cutting bit. Additionally, when it cuts, it barely makes any more sound than the router normally makes spinning freely, the old RZ bit was very loud when it was (barely) cutting. I even had an accidental command move this HQ bit cutting at a depth of about 10 mm through the pine, and though the motors were skipping at 300 mm/min, it still went through the wood a few centimeters before I could eStop the machine. Getting 10 bits at this price is amazing because the normal (and much less capable) RotoZip bits are around $8 at Home Depot. The only advantage with the standard RZ bits is that they are much longer, I can get about 20 mm of total cutting depth with these HQ bits, which is enough for my purposes. Now, my cheapo CNC can actually be used to make better parts for itself. I'm very glad I made this purchase, these bits make all the difference in the world for my CNC.