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Looks pretty solid and much easier than finger joints (my backup joint if this one doesn't pan) Do they play well with plywood?

You need a sturdy router table to do this.

You also need wood of cconsistent thickness.

John

I've used a locking rabbet bit to build the Dumble 2x12 out of lumbercore with good results. It never went on tour or anything, but I kick it around the basement.

In a speaker cab, the front and rear add quite a bit of strength.

For plywood, I'd like to see more lock and less miter than that joint has. I would think you could do a decent job mitering the outer third or so and rabbeting the inner two thirds with a couple of setups on the table saw. It would be trickier that one pass over the router table though.

After all that, it depends on the thickness of the material, size of the cab and intended use, but it probably would be fine.

Dan[/i]

Most likely I'll be doing 3/4" pine sides (which will get the miter joint) with 1/2" ply front/rear.

If you look at that picture the "lock" is on edge grain. I've never seen a lock miter on end grain. I'd really think that through and err on the side of safe.

My opinion is strictly as a non wood worker other than shop class 40 years ago.

In my view, look at the joint and the square surface area for a glue joint.

There is less glue surface in a joint like that compared to a dove tail or box (finger) joint.

To be simple, less meat in the joint.

Granted when a baffle and back panels are added, they surely make the box stronger but that joint in the OP seems rather complicated as in it has to be just right or it won't fit together.

Half blind dove joints seem pretty popular and you can buy jigs and make them with a router pretty easily.

I have seen 40 year old cabs with butt joints with and without bracing that seem to have held together OK.

You can make it as complex as you want really.

Normally the grain runs a band around the sleeve of the box.

I think the photo is just scraps or setup pieces.

John

Well I'm going to commit to a bit, so I hope it doesn't end up collecting dust. Found a pretty good video on it and they suggest running it in multiple passes (it does take out quite a bit of material otherwise and looks pretty spooky): http://www.youtube.com/watch?v=POvBhQo2ivQ

I'm not necessarily looking for the joint to end all joints. Just something that is relative strong and easy to execute on. If this doesn't gel... finger-joints it is!

The only reason I use finger joints on some of my cabs is for looks. My wood crafting buddy calls them Hollywood joints. Modern wood glues like Titebond etc create bonds that are stronger than the wood it joins. I used a rabbit joint on a solid pine cab recently, The wood had some minor cup and it really showed at glue up. My point here is the more complex i.e. increased surface area the more critical that the planks are truly flat or much unhappiness will occur. If I plan to gig / beat the crap out of a joint I will use a block to reinforce the joint. This system resists deformation of the joint as there is more material to resist compression.

Ask me about perfecting my finger joint jig which allowed me to test fit joints by hand. I thought I had arrived and was proud. Woodworking reality rudely intruded. The wood had minor warping which required a mallet to beat the joints together when all four sides were assembled. Some of the joints will need to be fixed / slivers of wood added like all of my finger joints.

Another alternative is to use pocket joints.

Of course it takes a special jig to do it.

But a lot of cabinet guys use them.

So you drill the holes, glue it up and screw it.

[img:500:500]http://tomsworkbench.com/wp-content/upl ... eg-jig.jpg[/img]

[img:591:393]http://www.macwood.com.au/images/Pocket ... joints.jpg[/img]

I was surprised when I got my Splawn Marshall head cabinet it was built using pocket joints.

I've had one of those pocket joint jigs since they first came out, saved my ass around the home and garage many times.

That pocket-joint jig looks like it might provide temporary relief from the pain-and-swelling of G.A.S. (gear acquisition syndrome). I think I'll order two today!

Is there a conflict between the length of the screws in pocket joints and a 1/2" cab round-over on 3/4 boards?
tony

Bah

echuta13 wrote:Looks pretty solid and much easier than finger joints (my backup joint if this one doesn't pan) Do they play well with plywood?

This is what you want for plywood http://www.mlcswoodworking.com/shopsite ... drawer.jpg
Its a bitch to get set up but once you do.it's off to the races.

I use it to make drawer boxes much better than dovetail or box joints I think I looks nicer too.