Iím looking for some feedback on what the best router bit may be for routing clean 3/16" wide and 1/8" deep flutes in white oak. They will be stopped flutes that we will use a plunge router and jig on. I need clean flutes and little or no burn on the ends. I was thinking about a down-spiral carbide?
(Solid Wood Machining Forum)
From contributor D:
I'm used to flutes being round bottomed and cut with a core box bit. I don't think they come in down-shear but that would be a nice solution if they did. I use 3/16" bits every day - two flute up-shear, straight bottom. Brand new bits will burn in white oak with the slightest pause routing by hand, even with very light passes.
I use a CNC machine and have worked out optimized feed and speed rates, but by hand I say pull up quick at the ends. You won't be able to be effective sanding in such a small groove either. A razor sharp chisel dragged in the groove can clean up burns pretty well, but itís much better not to get them. The tylosis in oak burns readily and deep. I know I could cut these clean and crisp with a CNC but by hand I'd get a few burns without at least a few practice swipes on a piece of scrap. A lot of old timers think skill with a hand tool is king. Stopped flutes is where skill with a power tool is king.
I simply use a long fence that I can clamp my stops to. Put the piece against the stop, plunge into the cutter, and run to the next stop. The other advantage over the router is it gives a nicer entry/exit slope than the router gives due to the diameter of the head.
If you don't have a shaper you could have a cutter custom made to do the same thing in your router table. Itís basically a rabbeting bit with the ends shaped. Otherwise youíre stuck with a regular off-the-shelf core box bit. For cleaning, simply grind the same profile into an inexpensive card scraper or other suitable implement and scape the flutes out after routing.