Joints Anyone

[4DThinker]

I've come across that same link several times, and I appreciate what the author has done. One of my goals is to use the CNC to improve the strength, simplicity of cutting, and variety of application for what look like more conventionally cut joints.

If I was going to make the pins on that 2x5 pin rabbet joint go through I'd change to profile shape of the pins to make them more interesting. Even if done using the same wood for both parts the end grain of the pins would be in contrast to the face grain of the board they show through.

4D

[4DThinker]

I had to put some trim around a table top I'm making, and had some 3/4 BB ply scraps wide enough to use. I wanted to make a corner joint that would pretty well lock together and take advantage of the plywood qualities rather than work against them. Did a finger joint test first. I got a clean front face but the plywood split out on the back face as the bit came through.

Thought a mitered corner would look nice, but wanted more interaction between the side and face. Wanted it to line up on its own, and not weaken either half in any way that might affect strength or looks. This is what I came up with. I'm calling it a Pinned Mitered Rabbet.

Fingers Test Inside

Trim Corner Test Inside1.jpg (1.37 MiB) Viewed 6334 times

[4DThinker]

Bad side of fingers.

Finger test outside

Trim Corner Test Outside2.jpg (1.4 MiB) Viewed 6334 times

[4DThinker]

Mitered rabbet.

Mitered Rabbet top view

Trim Cormer Pinned Mitered Rabbet1.jpg (1.42 MiB) Viewed 6336 times

[4DThinker]

Pinned face.

Through Pins. Could also have been blind.

Trim Cormer Pinned Mitered Rabbet2.jpg (1.37 MiB) Viewed 6336 times

[4DThinker]

Another View. I used the fluting toolpath on a parallel array of short lines to cut the mitered part of this joint on both halves. The plywood has 13 even layers, so I inset the pins exactly one layer from the inside edge. Left them cleanly cut. I now have my table top framed with this joint on each corner.

Corner View

Trim Cormer Pinned Mitered Rabbet4.jpg (1.49 MiB) Viewed 6336 times

4D

[HANNAH024]

Nice Joint. Perfect fit and It looks really strong too

[Hmr]

Excellent work! Thank you for the pics and tips you share here and elsewhere.

[4DThinker]

Nice Joint. Perfect fit and It looks really strong too

Thanks Hannah. Perfect fit is easy to do using the CNC, although this joint took a few strokes of a file on the inside faces before it would go together. The pins used the same vectors as the holes, but I used a -.005 pocket allowance on the holes so they didn't need a press to put together. You can make a joint so tight there won't be any room for glue. My students often wonder if they HAVE to use glue given how tight a CNCed joint may seem. Invariably their wood will shrink/expand a few times and that glueless joint will slip apart. So YES, they learn how to build in some tolerance so they don't have to fight assembly and can use glue.

4D

[4DThinker]

Excellent work! Thank you for the pics and tips you share here and elsewhere.

You are quite welcome. I didn't get my experience instantly, so I'll pass your thanks back to all those who shared their knowledge to inspire me. This is me paying it forward,

4D