Woodworker's Journal winter-2010, страница 23
to shank, this bit offers a 25/64" radius cove, a 5/16" bead, a 5/16" cove and a 15/64" bull-nose. There are a few different styles of this bit and the various radii may be different, but its functionality is the same.
This is a pretty large bit and is for router table use only. I also recommend using it with a 3hp router. There is a smaller version of the bit if you don't have a large router. Because of the large diameter of the bit, run it at a slower speed — around 12,000 rpm. If this will be your first large-diameter bit, you will find that it cuts amazingly easily. It seems wrong, but bigger diameter bits cut more smoothly than smaller diameters. This is due to the physics of the cutting action. The larger arc created by the tip removes the material at a more shallow angle than a smaller arc. This gives the same result as skewing a plane or chisel.
A few cautions before starting: When cutting any profile, I prefer to rout the profile on wider stock, then rip the desired molding off of the wider stock. That keeps my hands a safe distance from the bit. Also, using the lower sections of the bit's cutter will leave a fair amount of the bit above the table and exposed. For safety, I shield the top of the bit. I cut a section off of a PVC saddle connector and clamp that to the fence (see top left photo). This guard keeps my hands clear of the bit during routing.
Profile variations at a glance
Top portion of the bit is shielded here to minimize exposure to the cutter.
Roundover and Cove Top Roundover
Top Stepped Bead Top Double Stepped Bead
Top Stepped Ogee Edge Ease
Winter 2010 23