Need help aligning stacked dominoes

[Sam Shankar]

Hi folks,

I'm wondering if anyone can suggest a trick to aligning dominos for a butt joint in a 4x4 workbench frame that will look like this. These will be dry joints--I'll be using bench bolts centered in the joint to pull them together. (I may end up using smaller dominoes, but that's not relevant to my question.)

Left to myself, I'd either (1) plane the pieces so they are absolutely-positively-identical in height, and then use the fence to reference down from the faces on each side, or (2) use shims to reference UP from a flat surface. Is there another way I'm not seeing?

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[Matt Day]

You can use a shim to lay the domino tool on to do the top ones, and use the table surface to do the others. If that makes sense.

[Jim Becker]

Make a jig that allows you to mark things "identically" across all workpieces and be very careful about indexing off like edges. You'll need to slightly abrade shave the tenon end that remain dry so they can slip into the mortises snug but without the need of a mallet. I had to do that for a bed frame last year where I used 14mm Dominos plus the Domino Connectors for a knock down scenario. You might want to consider Domino connectors for this operation, too...very strong, they draw the joint together tightly almost like a draw-bore and they can be hidden...no evidence on the outside of the frame.

[glenn bradley]

I'm going to develop "Domino Centers" (think of dowel centers) and make a million bucks :D. I agree that accurate layout should get you there. Just use consistent reference edges and orientations.

[Sam Shankar]

Make a jig that allows you to mark things "identically" across all workpieces and be very careful about indexing off like edges..

Jim, I'm not sure I understand. Are you saying that I should mark both sides of the pieces?

[Kevin Jenness]

I like to index off one surface as you are proposing. In this case I would set the fence for the greatest offset and use a shim for the second set of cuts, but you could work off the bottom equally well. For horizontal alignment I would rely on fine pencil lines and the center mark on the cutter housing. You may need to remove the spines on the domino edges and chamfer the ends for easy entry.

[Jim Becker]

Jim, I'm not sure I understand. Are you saying that I should mark both sides of the pieces?

Think about this a minute...Domino mortises on either side of a joint need to be cut in "perfect" alignment both horizontally across a face and vertically from a face. So a jig to insure you cover that first part can be really helpful. In this photo, I recently took an existing hinge jig I had made and put a couple of holes for a pencil to insure that the two Dominos in the joinery were lined up consistently across the workpieces to be joined. While it's sitting up on the workpiece, the wood part is essentially a fence and there are two holes spaced appropriate for "this" joint. You can see the left one, but the right one is barely visible because of contrast...but it's there. The lines on the workpieces were drawn using this jig and I'm happy to say, everything lined up such that the doors I was making were really close to square when assembled and pretty much exactly square when tweaked. And that was with using the "tight" setting on the Domino tool.

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For the other data point, one must index from the same face so that they line up vertically...that gets pointed out a lot for Dominos, biscuits, dowels, whatever, and should make sense.

Where your challenge comes from is that you're using four tenons. In an ideal world your pieces will be exactly the same thickness so you can index data point number two from adjacent faces since the Domino machine has limited depth you can sink it down for the second row of mortises. If things are not the same thickness but still thick, you theoretically can still measure down from the same face as the first row as long as you use the same offset across all of the joints and have a steady hand on the tool.

[Charles P. Wright]

I would use my table as a reference, clamp down the workpieces (or the mating surface I would clamp "up" at a 90* angle to the table). Then use the base of the domino to reference one, using the paddles or guide to determine the width. For the stacked domino, I would put a board between the table and the domino base. I find using the base can often be easier/more precise than the fence.

[Jim Dwight]

I've only had a domino for a few months so I am still figuring it out. I'm making a dresser I have built before without any dominos but, instead, I am maximizing my domino usage on this one - largely for practice. I have found it very helpful to make a very simple marking gauge to put the domino position on the pieces that will be joined. I used a scrap from a bed I made of cherry what was about 2 inches wide and about 3/8 thick. I glued and brad nailed another small scrap on to act as the registration point - fence. Then I drew lines with a 0.5mm pencil around the cherry scrap where I wanted the dominos. Now I use the same simple jig to mark both pieces. It has worked well. I use the tight setting on both pieces but the alignment is good and the joints go together fine.

For your case, you could mark lines on both faces and they will align using a simple jig like this. You could even just use a Incra marking jig to mark the position.