Any self alging joings for MDF?

[knight_toolworks]

I have some prototype speaker cabinets to make and they have radiused corners so they will be butt joints. It would be nice to cut out joints that just fit together without biscuits. Any idea’s?

[kirkkelsey]

Blind Dado! Once we figured out how to do them (CAD to CNC) they have been the staple of my cabinet construction designs.

[knight_toolworks]

I can't be a dado as the edges are flush. there will be some blind dado's on the inside. I could do rabbets but that will not hold them together. maybe 1/2 a rabbet or I was thinking a big finger joint.

[kirkkelsey]

The Blind Dado joint for our cabinet corners consists of milling a 3/8" thick tongue on the end of one piece and the stopped dado slot into another.

The Tongue is done by doing a pocket over the tongue to cut the tongue to thickness, and followed by a profile/outline cut around the entire piece.

Keep in mind the outside face of your box is Up for the part with the Tongue, but Down for the part with the dado (as opposed to the faces inside when we build cabinets). You may need to nest your parts in two different batches if your material only has one good face side.

This screen capture of the joint in the 3D solid model does not show the radius from the bit, as there are the rounded corners at the end of the dado, and the base of the tongue. We make the dado one bit diameter longer than the tongue (or the other way around with the tongue being one bit diameter shorter than the dado). It may take some test runs to determine your clearances, but this is what we use with a 1/4" bit (0.246" diameter).







6482

[bill.young]

Steve,

You might look at this thread that Mike Richards started for some ideas..

http://www.talkshopbot.com/forum/messages/29/21849.html

Bill