CNC Box Joint (Milled Flat)

Test fit of box joint parts. For this test I have 'cheated' on the inside corner mating surfaces by just hollowing out a channel.
Fingers are slightly too short because plank is slightly thicker than nominal size and I forgot to measure and add a bit of extra safety margin.

[@edwardhandrich6043]

Lightbulb moment. If a square peg doesn't fit in a round hole, make a round peg. Great video.

[@gravirika]

Please share the file

[@robertlikavcan1273]

Pls share file

[@JohnColgan.]

Nice looking joint, I'm trying to get my head round them for some drawers next week. 200mm each. Strong tendency to go normal tablesaw/router jig and practice CNC for another time

[@pablo4youtube]

Woodworking and CNC hobbyist here. Two central issues for future reference when you do CNC box joints: (1) Modify the toolpaths for tighter tolerances - box joints by definition should be tightfitting - they should require a little bit of effort with a rubber mallet to get into place. It's clear in the video that they slide in and out pretty easily, which defeats the purpose of a good box joint. (2) you need to adjust the length of the box joints; when you fit the pieces together, it's clear that the male ends are sunken in while the female receiving gaps are proud. You actually want the opposite. If the fingers are too short, it just looks wrong. If you purposefully make the fingers longer than the receiving gap (which is called keeping them proud of the surface), you can then hand or orbital sand them down to a perfectly smooth surface that looks like a million bucks. Implement those two changes and you'll have reliable joint rigidity and beautiful appearance. You're off to a great start. Keep up the good work.

[@jamiekawabata7101]

Great points. Thank you!

[@martyn1678]

you need a bit of room for glue, no good being so tight all the glue get pushout when assembling

[@PuppetWood]

Very nice ❤

[@BlainesGarage]

Excellent.

[@tomm3183]

Nice what did use to generate the tool path?

[@jamiekawabata7101]

In this case I used Estlcam to generate four separate jobs and spliced the gcode together. 1: 2D perimeter at 4mm depth with finishing allowance. 2: 3D surface restricted to tops of fingers. 3: 2D pocket at depth 4mm for base of fingers. 4: 2D perimeter with holding tabs and roughing + finishing pass.

[@kyforge]

what created the fingers for Esltcam to route 3D? I have Estlcam but only could use an STL files for the curved fingers. ??