Router bits size and single pass

Hi, I have two question related to CNC.

  1. In the manufacture guide, it’s recommend to " Use 9.5-12.5mm router bits to cut 18mm plywood in a single pass." Here in North America with imperial system, shall I use 3/8" or 7/16" ?
    3/8" = 9.525mm
    7/16" = 11.1125mm
    1/2" = 12.7 mm
  2. Any more information on how&why to make the cut in a single pass? From what I learned from others in our local maker space, it’s better to make more shallow passes at a higher feedrate, and the depths of cut is half of the bit size. e.g. if the bit size is 10mm, I should set maximum roughing stepdown to 5mm. 18mm will take 4 passes. I have not tested this yet but I’m eager to hear your experience.

Thanks and really appreciate your answers!


We do a single pass with an 8mm compression bit, so 3/8 should be fine. More passes often lead to a nicer edge (not super important for house framing, more important for furniture) but tend to take much longer to cut. It’s a trade-off.

I use a local brand called tungsten and tool, but I hear whiteside and amana are great options in the US. I’ve also used Spetool to a pretty good result, but again, I probably wouldn’t use Spetool for furniture as it’s a bit rougher than some of the more premium brands.

1 Like

Based upon the level of obsession laser focused onto their products, as displayed in YouTube videos, Harvey Tool appears to know what they are doing in the extreme. Worth a try. PhD level obsession is displayed therein.

1 Like