Joint I Saw Being Made

Was at a fellow CNC’rs place. He showed how he made this joint. “OMG Becky look at her xxxx.” (you got to be old to get it).

He made this small piece and joined it. I was so amazed. No glue

Being that it was pine, I thought it would snap as he was cutting it or when he tapped it together. WOW

He was using an Avid machine and ASPIRE


This is known as a Knapp joint (for the inventor) or a “pin and cove” (descriptive name).

It’s a distinctive appearance, and has the advantage of not requiring special tooling, but it does require a vertical fixture such as:

and then at minimum 3 operations:

  • cut parts to length/size and machine interior features (rabbet for a bottom/lid, &c.)
  • mount all four boards on the machine and cut the joint for two corners
  • repeat for the other corner

If you don’t set up the file for cutting two corners at a time, it’s 5 operations.

An alternative is to use joinery designs which allow cutting the parts flat on the table — for the photo for the box below, no glue was used:



I’m working on a simpler version which will allow test fitting first, and won’t require the narrow V endmill:


Thank you Sir !!!
I looked through the forum last night, finding out it was a Knapp Joint, not getting much farther. The info you provided looks great.