Square Interlock Corner Joint

Square Interlock Joint

This joint, cut on my CNC, could easily replace half blind dovetail corners for strength.  It can only be assembled in one direction.  It won't pull apart sideways.  As with many of the CNC joints I've come up with it uses the same vector for both sides of the joint.  One side is cut on the end of a board clamped vertically.

Side A. Clamped Vertically

The other side is cut on the end of a board clamped horizontally. 

Side B.  Clamped Flat.

This joint is half blind, showing only on one side of the corner.  

All the corners are rounded to account for the 3/16"diameter end mill used to cut the joint. A sharper cornered version could be cut with a 1/8"diameter bit if the cutting length of the bit was as long as the boards are thick. 

This sample I made from some pine board scraps.  When both sides were cut they slipped together easier than I expected.  This suggests that the bit I used was a little bit larger than .1875" in diameter.  More than enough room for some glue. 

Sample Ready to Assemble

The positive and negative sides together look a bit like a zipper.   

Partly Together

Drawer sides would be a good place to use this joint.  A drawer that holds sewing supplies would be a perfect application for it!

Glue Together and Sanded Flush

As with dovetail joints, the spacing between squares could be varied for a more personal design. Imagination and the size of router bits are the only the limiting factors. 

4D