Difficult to use. Requires a precisely adjusted router guide and many test cuts. In addition, the joint fits. The connection didn't fit perfectly after getting the cuts as good as I thought I was going to get. In the end I decided to abandon the locking miter joint in favor of a simple miter joint. Also, the bits don't feel as sharp. I had to cut slowly so the router table didn't get stuck. The design can be improved by adding a bearing, improving the die head and maybe changing the die head profile to make the connection cleaner.