erikbojerik Posted May 31, 2007 Report Share Posted May 31, 2007 (edited) OK, so I had these router bits custom made for me by a machine shop contact, to the tune of $200/ea. I'd got a bunch of quotes from commercial manufacturers that were all in the $265 to $315 each, so I think I got a good deal in that respect. They are a bit pricey but because I am finding my free time is not what it used to be, I am reveling in the fact that I can now radius a fretboard in ~5 minutes. Here's the tutorial for those who asked. 1) These are used in a router table (mine's a fairly cheap Craftsman), I'd never use them in a hand-held. The bearing runs more or less along the centerline of the fretboard blank. First bit of business is to plane square and true a block of wood longer & wider than the fretboard, so that you can mount the fretboard centered on one side and not have the edge of the board touch the router table. I used a 4x4 mailbox post for this, planed & squared up on the jointer. Fingerboard blank has already been planed flat by this point; the board pictured is a birdseye maple fanned-fret board with integral binding, slotted but not yet tapered. 2) I'm using the 16" radius bit for this board. I raise the bit so that the lower edge of the bearing is on the centerline, then make two passes, flip and make another 2 passes. Normally this does the job on the outer half of the board, you can see there's a strip down the center that hasn't been radiused yet, and this is clearly shown by the radius gauge. 3) Now iterate...raise the bit, make a pass, flip and make another pass, keep raising the bit a little at a time until you just eliminate your centerline on the board. This leaves a subtle ridge down the center of the board that is ever so slightly high, easily knocked down with ~10 strokes from a sanding block (I used a radius block I already had on hand). The result is a radiused board with a precise uniform radius that is even across its width...no more fretboard with assymetrical radius! The surface here is very nice. This was a board that I got a fair bit of tear-out from the jointer, so I had to use a drum sander to bring it to proper thickness. I got no tear-out at all with the radius bit, even though the board was already slotted. Here's a shot of the finished product, after knocking down the center ridge. Edited May 31, 2007 by erikbojerik Quote Link to comment Share on other sites More sharing options...
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