Festool Domino Joinery Advice

[David Wadstrup]

Hello,

I am building a 21" deep cabinet in which I'll need to join the top to the sides with miter joints, and the bottom to the sides with butt joints. Of course, these are very weak joints that will need to be reinforced. To those of you have experience with them, would Festool Dominos provide the strength that I'll need without having to use additional fasteners or supports or reinforcements or such? The overall case is 24" high, 36" wide, and 21" deep. All made from solid wood, not ply.

I'd love to hear what you think. Also, if you know that Dominos would NOT be sufficient, what sort of additional structural joint support would you recommend? Pocket hole screws?

Thanks for your advice.

[Wade Lippman]

You might have trouble assembling it because the butt joints are a different angle than the miter joints, but dominoes are plenty strong. Is it going to have a back? They add a great deal of rigidity to a cabinet.

Assuming it will not be seen, I might put the bottom on with pocket screws because they won't interfere with the assembly.

[Jack Jackson]

Kind of depends on what exactly this cabinet is going to be used for... but the short answer is yes, Dominoes will do just fine. They're extremely stout when put in solid wood. You can't really pocket screw the top since they are miters but I would Domino + pocket screw the bottom since those will be hidden. Since the top will be mitered and the bottom butt joints I don't see a problem with glue up - just do the bottom first then slide the top on with Dominoes. The setup for Domino-ing miters is a little tricky at first since everything has to be dead on accurate or the mitered edges won't align but just use test pcs and once you get it set up it's quick and easy to do the mortises... You sound like maybe you want to do Dominoes without any other supports and that would work fine as long as you're not going to be storing anything heavy on the top of this cabinet. If you were I might add a couple of small corner supports on the inside between the top and sides to give those miters a little extra support. I've only done 3-4 boxes/cabinets with miters + Dominoes but that's my experience so far.

[Peter Quinn]

Dominos work well for reenforcing miters, keep in mind you wont be getting a very deep domino in a miter, and as noted assembly will get tricky as its monolithic. Is the bottom flush with the corresponding parts on the sides? If not a sliding dovetail would be strong and more traditional, easy enough to construct. If the bottom is flush dominos would work, pocket screws could work, a tongue and rabbit could work, a spline could work, lots of options there. Dovetails are probably the strongest and most traditional method for solid wood case construction, box joints work well too (lots of glue strength).

[Harlan Barnhart]

Hi David, I agree pretty much with Jack, if you have a domino, use it, It will work fine for this application. I would put them on three or four inch increments. There are other joints that will work as well if you don't have a domino. Splined miters are quite strong and easy to clamp, the butt joints could be made with box joints, dove tails, or a simple dado joint. On the other hand, if you are looking for a good excuse to buy a domino, go for it. I use mine regularly in many different applications.

[Mike Henderson]

I'd definitely use half blind dovetails for the bottom. For the top, it depends on what you want the top to look like. You could do a spline that would be hidden and would be very strong.

The problem with the Domino is that you won't be able to put them very deep - unless the wood is pretty thick. You have to make sure you don't go all the way through. The Domino would not be my first choice for that joint unless you're working with some really thick wood.

Mike

[David Wadstrup]

Thanks for the advice, everyone. Sounds like Dominos should be sufficient. Of course, dovetails and some of the more traditional joinery would be strongest. In this case, however, speed of joining is a priority.

Thanks for the heads up on the difficulty using BOTH mitered and non-mitered Dominos will create when assembling. I hadn't thought of that, and am appreciative of you all saving me the headache. I've read that some people will miter the board AFTER the Domino mortises have been cut. Do any of you have on suggestions, advice, or tips on doing this?

Thanks again!

[Harlan Barnhart]

I've never had a problem putting dominos in a carcass miter after it is cut, just keep in mind it is done from the inside so the top and sides must be the same thickness or the outside will not line up.

[Jack Jackson]

I haven't ever done the Domino mortises before the miter.... I guess if you cut the mortises at 90 degree angles as if you were going to do a butt joint, then cut the miters that would work (at least it seems like it would in my head)... I've just always cut the miter, cut the mortises into the 45 degree face of the cut on both sides then slid them together. Anyone else use this "mortise now, cut later" thing?

[Harlan Barnhart]

I've never seen it done, but I suppose it might work, You will get more tenon length if you put the mortises in perpendicular to the miter cut.

[Chris Padilla]

I guess you could do the mortise first on the miter but you'd want the mortise fairly low in the edge so you have some meat to go into the side piece after it has been mitered. It sounds fine to me. I might give it a shot as I hadn't thought of it that way.

Dominos, pocket screws, glue...they are all good and strong and will work just fine.