Thought I would pass on my latest discovery that has improved my cnc experience. Bottom Line Up Front: single flute bits seem to be a good match for lower power hobby cnc machines… they enable you to run at lower feed rates while maintaining a decent chip load.
I’m not sure why 1F doesn’t offer single flute bits for sale in their online shop… If there is a downside, I haven’t found it yet.
If any of you more experienced 1F cnc’ers have experience using single flute bits, I am interested in hearing about it… particularly if there is something that you do not like about them.
I purchased a dozen cheap Chinese bits… 6mm, 4mm, and 3.175mm to give them a try. They are tungsten carbide and that one cutting edge is razor sharp (I actually sliced my finger when I carelessly removed the bit from the packaging). I noticed that Amana and Datron have them if you prefer US made bits… I have not been able to find a cheap round nose single flute… so I’ll probably be purchasing a Datron soon.
Yea… I ran across an article that recommended them for hobby level machines… and that was the best tip I’ve had… I have found that the makita router does a much better job pulling the one super sharp flute through the wood with much less vibration and noise than any of the two or three flutes bits that I have.
Sure… I try to stay close to the feed rate from this simple formula:
Feed rate = Router RPM x Chip Load x Number of Flutes
…for the hardwood that I am cutting, I am running the Makita router at approximately 10000 rpm which is about 1.5 on the speed dial. A reasonable chip load for hardwood is .008" to .01"… which gives:
Feed rate = 10000 x .008 x 1 = 80ipm
Feed rate = 10000 x .01 x 1 = 100ipm
… and even if you drop a little below that… say 60ipm, you are not rubbing and burning up your single flute bit.
The obvious outcome from the formula is that with a 2 flute bit, you are up to 160ipm to 200ipm to get the same chip load… and if you slow it down too much… say 60ish or below, you get a chip load that is less than .003" which starts to put you in a zone where you may rub and heat up your bits (which is what I have done). Of course 3 flute bits are even worse.