End Mill Cutters

by Bruce Scotten

Originally published in Guild of American Luthiers Data Sheet #149, 1980 and Lutherie Tools, 1990

The use of routers to cut channels for binding, purfling, and rosettes is quite common. One problem associated with this tool is tearing and chipping caused by the use of standard router bits. A simple solution is to replace router bits with end mill cutters. Their advantages are: the increased number of cuts per revolution (4, 6, or even 8 flutes or edges, compared to 1 or 2 on router bits); plus the right-hand cut, left-hand spiral option which cuts with a downward motion that prevents the hairing and tearing caused by right-hand spiral lifting, and the slapping effect of straight router bits.

End mills are more expensive than Stanley or Sears router bits. Solid carbide, 1/4" shank, 1/4" cutter, right-hand cut, left-hand spiral end mills are about $20. However, decreased down time and improved product performance make end mills a sensible alternative for the serious luthier.

End mills are used more in metal working than wood working. Therefore any machine shop should be able to direct you to a jobber specializing in cutters. Johnson Carbide products in Saginaw, Michigan is a reliable source for end mills if you have difficulty locating them in your area. ◆