Ive been running a 2 flute Whiteside Ru2100 for a little while now and its held up but im seeing it get a bit burnt due to not going fast enough. Im running 45 IPM roughly in soft pine and poplar and the spindle is turned down with one of those harbor freight router controllers. I really dont know how much more I can push the IPM.
I know that im better off with a 1/8 single flute end mill but it really cuts down on carving time with a big 1/4 EM.
Any suggestions on a single flute 1/4 end mill upcut? Or should I stick with the tiny 1/8th end mill and run it hard?
Im reading some guys say here run it slower IPM and go deeper DOC to say 5-6MM with a 1/4. Is that true I thought we were better off running shallower cuts?
I just cut a chunk of cherry on my 2x4 primo with a 6mm mill (slightly smaller than 1/4in) at 0.2in DOC. I think it was 20 or 24ipm, but I’m using a 611 that I can turn down to a fairly reliable 16k rpm. I’d go to at least 1/4in in pine on a pocket path.
From my reading on bits for cutting plastic (since I’m not happy with the edge quality of cutting plastic with my general router bits), the geometry of a bit for cutting plastic is different than the geometry of router bits for cutting wood. Doesn’t mean it won’t work, but perhaps it is not ideal.
When I did a search on Amazon, I found half a dozen single flute router bits in a few minutes of searching. They are all described as ‘O’ bits. I wasn’t sure what that meant, and found this reference. Still not completely sure of the strengths and weaknesses of an ‘O’ bit.
Note that when I’ve searched out plastic-specific bits, I found them to be very pricy, so the modest price of the bit that Barry pointed out is interesting.
Our stepper motors have more torque at lower speeds. Anything under 10mm/s is probably close to the same. Too much faster and the torque will drop off.
In general, the load goes up proportionally with the depth and proportionally with the speed. So if you can handle more load, you can go deeper or faster. But if you go faster, you may lose torque (and if you lose too much, you will skip steps). This is why the recommendation is to fo deeper before faster. 6 or even up to 8mm DOC is doable on some machines. I’ve done it on my low rider. If you are not cutting a whole slot, like on a finishing pass or a lower stepover on a pocket, you can also handle a lot deeper.
The counter argument, or the limit to that logic, is that you still need to get the darn chips out. It is harder when you are cutting deeper.
As for 1/4" bits, they make pretty close to twice the load and are twice as wide. If you are doing slots, then you will have to go at half the speed. You’re wasting time making extra dust. If you are doing pockets, you will go half the speed, but cut half as many lines, so it works out to a little faster.
Where 1/4" is better is if you have a very rigid machine and you can push the bit hard enough to flex it (a lot) or heat it up. The 1/4" will not heat as fast and not bend as much.
I think 1/8" is generally a pretty good balanced size. There is a good reason why table saw and miter saw blades are about 1/8". It provides some ability to make a tough cutter, but doesn’t waste a bunch of material and effort cutting a big fat kerf. It also feels about right. Like the 1/8" bit for cutouts and 1/4" bit for pockets, is similar to using a dado blade for thicker cuts.