How to Cut Domino in a Thin Piece of Wood?

[onocoffee]

I’m trying to do this properly. In the two chairs I’ve built, I’ve really approached these mortises with some measuring but mostly by using “The Force.” The one is the pic is slightly off.

I’d like to figure out a better and more precise method.

Yesterday, with a shorter back piece, I struck center lines to align with the center marks on the DF500, and then made the mistake of plunging it by hand with no clamps (the DF500 was in a dock).


Any thoughts on how to more accurately drill these 10mm mortises? I’m shaping them on an oscillating sander and can’t say my dimensioning is perfectly proportionate.

You can see in the second pic the muck up and the other two back pieces I’d like to mortise today.

Thanks!

 

[jeffinsgf]

I would suggest cutting the mortises while the workpiece is still rectangular, then cutting the profile afterwards. That way you have better alignment to the mortise position and something firm to reference from.

 

[woodferret]

Clamp a block 10mm offset (assuming you're using a DF500) from the mortise and then use it to register against the bottom of your DF500. You may want to see the supplemental manual on mid-panel dominos.

 

[Sparktrician]

I would suggest cutting the mortises while the workpiece is still rectangular, then cutting the profile afterwards. That way you have better alignment to the mortise position and something firm to reference from.

That would be a much better solution for keeping the work piece square and true. Also cut two template pieces the same size as the work piece BEFORE cutting one to the finished contour so that once you get this right, the remaining work pieces will be far easier to duplicate.

 

[smorgasbord]

I'll semi-suggest getting a CNC (small one is fine) and cut both the mortise and the outside shape with that.
Then use a pattern bit in a router/router table to finish the outisde shape, since the piece is thick.

If you don't want to buy or have the space for a new multi-thousand dollar tool (which is incredibly handy for lots of things, btw), then the two suggestions above are good.

This is also a potential application for my Face Mortising Jig, which you can build yourself - see https://festoolownersgroup.com/threads/domino-face-mortising-jig-any-interest.75046/ Use double-stick tape to hold the stock to the jig, assuming you don't have a lot to do.

 

[ChuckM]

As you've already cut the pieces to their final and small sizes, you need to enlarge their registration surface. One way to do it is surround them with spacers or a cradle roughly of their shapes (everything can be double-face taped to the bench) . Extend the intersecting lines of the center point and align the DF base with those lines.

Whether you hold the machine freehand and plunge or clamp a fence as suggested by woodferret depends on your comfort level.

Btw, you can plug the mortise and re-mill the mortise, if desired. Most Domino blunders can be fixed.