Domino joint newbie question

[lfparker]

Hi

I have an interesting dilemma.  I need to join a 2 inch rail to a 2.5 inch post.  I was planning to make two rows of two mortises in both the rail and the post.  Since the rail and post are different thicknesses I'm wondering how I line them up to get an accurate fit.  I could see it's pretty easy if I only wanted to use one row.  I would center the mortises on both workpieces.  But with two rows it seems like it would be difficult to get precision on both workpieces especially since they are different thicknesses.  Thanks for your help!

Lewis

 

[bkharman]

You could reference off of the first domino. If I get your question, you want them to be "stacked" vertically.

If this is the case, layout the marks for the first one, ensure it is proper, then slip a domino in on both parts and mortise above (or below) it. If this isn't what you are looking for, doodle up a little sketch to help out.

Cheers. Bryan.

 

[Pretzel Logic]

Hi

I could see it's pretty easy if I only wanted to use one row.  I would center the mortises on both workpieces.  But with two rows it seems like it would be difficult to get precision on both workpieces especially since they are different thicknesses.  Thanks for your help!

Lewis

You would only center the mortises on each piece if you wanted the rail centered on the leg, but I wouldn’t worry about centering a rail on a leg.  I would only worry about the correct reveal or offset from the outer face of the leg I was looking for.

Flush, or no reveal would be the most simple.  If I wanted a reveal with only one row of mortises, I may just alter the fence setting for each piece.  With two rows of mortises on each piece, I would use a shim appropriately sized for the reveal.

If for example, I wanted about a 1/4” reveal, I would use a small piece a plywood or MDF about 1/4” thick.  You could mill up a shim any thickness you want, but make sure it is uniformly thick with parallel faces.

Use the shim between the fence and rail when making the mortises on the rail.  Make the 1st row of mortises then remove the shim and make the 1st set of mortises on the leg.  Set the fence depth for the 2nd set of mortises and repeat.  This will offset the mortises on the leg by the thickness of the shim.

As with most woodworking, using the domino requires careful consideration of reference faces, edges and ends.  Keep track of those and it should go smoothly.

Good luck, Ed.

 

[lfparker]

Thanks Ed I appreciate your response.

Lewis

 

[Stone Message]

Hi Lewis

I do not think that this is difficult at all. I assume that your dominos will go vertically (if the post is upright).

Regardless of whether you use the DF500 or DF700 you can set the height below a reference face using the height gauge to the left of the Domino front frame.

You can easily mark a centre line on the post which, if needed can be continued around to the other face.

With the DF700 you could probably do everything from one face but with the DF500 you will need to do some simple maths.

I have attached a diagram which may help you to figure it out.

If your rail is 12 mm thinner than the post then x1=d1+6 and x2=d2+6

Peter