domino layout assistance

[rodger.]

As my workbench plans progress, I am beginning to look a joinery options. Mortise and tenon are pretty common here, but I thought i could quadruple domino it for a super strong joint.

Anyways, I usually rely on center lines for dominoes. I set the domino to cut a mortise in the center of the stretcher/apron, and cut. Then I reset the fence to cut the center of the leg (always different thickness that the apron). If I need two dominoes, no problem. They are in the same center line.

If I want to use 4 tenons (two rows of two), my center line approach will be far more complicated, as I will need to accurately calculate offsets. Anyone have an easy way to do this, so that all 4 dominoes line up perfectly with their mortises?

 

[jjongsma]

I suppose you could simply use a spacer against the fence so you can do one row, then remove the spacer and then do the other row? Same spacer would be used for the leg mortises.

[rodger.]

1 minute ago, jjongsma said:

I suppose you could simply use a spacer against the fence so you can do one row, then remove the spacer and then do the other row? Same spacer would be used for the leg mortises.

I need to ensure that the space between the 2 rows mortises in the leg and apron are a perfect match. Maybe I'm missing something, but how would the spacer ensure the correct spacing between the tenons? Can you elaborate a bit?

[rodger.]

This joint is easy, as the dominoes are aligned using stock of the same thickness. Fence setting stays the same.

[Eric.]

As much confidence as I have in Domino strength, I think the better joint for a workbench base is a drawbored M&T.  It has to endure a lifetime of lateral forces and serious abuse.  A lifetime of abuse is a lot of abuse.

[jjongsma]

18 minutes ago, rodger. said:

I need to ensure that the space between the 2 rows mortises in the leg and apron are a perfect match. Maybe I'm missing something, but how would the spacer ensure the correct spacing between the tenons? Can you elaborate a bit?

Well, it's possible that it's me that's missing something. But when I think of things that are different offsets but need to line up, I think of using a spacer. Having never used a domino, it's possible that there's some reason that this wouldn't work on a domino.

For example, start by setting the fence for the mortise farthest from the reference face of the thicker stock. Leave the fence there. Cut those two mortises, then mill up a spacer (A) with thickness equal to the distance you want between the mortise rows and place that spacer between the domino fence and the stock. Cut the top row of mortises. Then mill up another spacer (B) equal to the apron offset. Cut the two far mortises on the thinner stock using the apron spacer (B), and then use both spacers (A+B) to cut the other row.

Like I said, I've never used a domino so maybe there's some reason that doesn't work.

[rodger.]

Thanks for the idea - I wonder if others have tried this technique.

[shaneymack]

1 hour ago, jjongsma said:

Well, it's possible that it's me that's missing something. But when I think of things that are different offsets but need to line up, I think of using a spacer. Having never used a domino, it's possible that there's some reason that this wouldn't work on a domino.

For example, start by setting the fence for the mortise farthest from the reference face of the thicker stock. Leave the fence there. Cut those two mortises, then mill up a spacer (A) with thickness equal to the distance you want between the mortise rows and place that spacer between the domino fence and the stock. Cut the top row of mortises. Then mill up another spacer (B) equal to the apron offset. Cut the two far mortises on the thinner stock using the apron spacer (B), and then use both spacers (A+B) to cut the other row.

Like I said, I've never used a domino so maybe there's some reason that doesn't work.

This is the exact way to go about this. 

[Larry Moore]

I don't use the fence to do what you are trying to do. The domino 500 will give you the mm equivalent of 3/4 inch to the center of the cutter from the base.

So I would set a spacer equal to the set back and plunge the leg then plunge the apron sitting flat on the table.

To get the second row, just add a spacer of the needed thickness.

[wdwerker]

I make a spacer the thickness of the setback. Then set the machine for the deeper cut and do all of those mortices using the spacer on the aprons. Reset the fence & repeat for the outer row.