I recently found myself needing a two-flute router bit with a bearing mounted above the cutters, like the one Mark Songey described in “Timbers and Templates” (FHB #10, p. 38). My supplier didn’t have one, and I didn’t feel like waiting for the postman. So I pieced one together using readily available parts.
I started with a two-flute carbide bit (a Bosch #85230, 5/8-in. in diameter). Next I located a guide bearing of the same shaft size and outside diameter as the cutters (Fafnir Sl- K7), and a short Oilite bushing ( 1/4-in. i.d. by 5/16-in. o.d. by 1/4-in. high). The bearing slips over the shaft, and the bushing keeps the bearing close to the cutter — provided that the bushing is touching the collet. This contact is important because it eliminates any up-and-down play in the bearing.
The system works quite well. The parts cost about $22, and they were all easy to find.
—Josh Rothman, Toledo, OH
Edited and illustrated by Charles Miller
From Fine Homebuilding #13