Mortise and Tenon Joint: :

The Mortise and Tenon Joint is for structural members and, more specifically, for use in construction of wood structures. It drills a flared round mortise, which makes the bottom of the mortise wider than the top.

You cut a slit into the tenon (Figure 3), insert the skinny edge of the wedge before you drive the two together. It forces it into the tenon. Figure 4 shows the end result.

The bottom of the dovetail expands when power is applied to the drill or router, cutting flared bottom in mortise (Figure 2-B). The relative dimensions of the mortise, tenon and wood members may be varied depending on the application.

Figure 1:  Side sectional view of a first member including a round, unflared mortise:

Figure 2-A and 2-B:  
Close-up side view of an exemplary bit for use in forming a joint; the bit is contracted:

Figure 2-A:   Figure 2-B:  
Insert dovetail mortising bit into mortise. Bottom of dovetail mortising bit expands when power is applied to drill or router, cutting flared bottom in mortise.

Cutting ridges do not reach the bottom of the bit. This keeps the bit from making the mortise deeper than originally cut.

Figure 3:
  An exploded side sectional view of an exemplary joint, showing a first member including an exemplary flared dovetail mortise and a second member including a slotted tenon with a wedge disposed in the slotted tenon:

Figure 4:  Side sectional view of an exemplary joint: 

The inventor is looking for a licensee

Inventor:  Joe Pescatello, 350 Sagamore Rd., Rye, NH 03870
[email protected]