Shop Lee Valley Bird’s-Mouth Joinery Bits

Historically used in the construction of masts and booms for wooden boats, the bird’s-mouth joint is straightforward to make, stronger than a traditional miter and, with nesting joints, easier to glue up without shifting.

With these three cutters, it is a simple matter to make 6, 8, 12 or 16 sided hollow columns, as well as straight or tapered multi-sided planters, bowls, etc., all of which can be left multi-faceted or planed/sanded round. Generally, more sections are required for larger-diameter assemblies to keep the wall thickness to a minimum and reduce the amount of material to be removed when rounding.

Designed to produce flush joints with material up to 7/8″ thick. Thicker material can be used, but will require some dressing after glue-up. Holder included with each bit. Shank diameter is 1/2″.

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 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.