Lee Valley Thumbnail Bits

Our professional/industrial grade bits have tungsten carbide inserts ground on CNC (Computer Numeric Control) machines using 600x diamond wheels. Tungsten carbide maintains its hardness at high temperatures and holds an edge far longer than high-carbon or high-speed steels. The bit bodies have a non-stick coating for easy resin removal. 

For better safety, these thumbnail bits should be used only in a router table equipped with a fence and not used free hand.

Each bit includes an advanced polymer friction-fit holder that can be mounted horizontally or upright.

Replacement bearings are available separately. The 1 3/16″ diameter bit uses a 3/8” × 3/16” bearing; the 2 1/2” diameter bit uses a 1/2″ × 3/16” diameter bearing.