Incra Double Dovetail Project #2: Cutting the side joints

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Blog entry by SPHinTampa posted 10-07-2011 04:07 PM 9699 reads 3 times favorited 3 comments Add to Favorites Watch
« Part 1: Prep Work - creating the laminated stock Part 2 of Incra Double Dovetail Project series Part 3: Cutting double dovetails and making a few mistakes »

First step of a double dovetail is to cut a through dovetail on each side piece and then attach a trim piece. This blog entry will cover that process.

So starting with the end pieces and a 6” piece of trim stock (same width as the side piece, thickness doesn’t matter).

Install the two template strips into the positioning system (1 dovetail strip and 1 double dovetail strip).

The dovetail strip consists of an A side which lets you cut pins at 7/8” intervals and a B side that is offset by half that lets you cut the tails. The double dovetail side lets you use the same bit but you make double cuts that expand the slots to accommodate 3/32” trim outline. So you have a C/D cut for the pins the shrinks them slightly to accommodate the trim pieces.

First trick is to get the jig centered. That is done by roughly aligning the center of the bit with the center of the board with the jig locked on the centering mark on the template. You then cut a groove through the center of a scrap piece that is same width as your work piece. Reverse the piece and re cut the groove. Then adjust the jig, using the micro adjust feature, to the get bit evenly centered in the groove and move the template to re align the centering mark.

Then, as is required in all dovetail jigs, you must make test cuts to get the bit height set. This is done by making two cuts on the edge of two boards and then test fitting them.

If the fit is tight, you are done, otherwise – you raise the bit if the joint is loose or lower the bit if the bit is tight. The template will give you the initial setting for the height. First cut was a little tight.

With the height dialed in, I use the double dovetail template to cut the pins on the end pieces. This is done by taking a light scoring cut on the outside of the piece and then slowly advancing jig to first pin cut. Then you just move the jig forward on each cut and use the right angle jig to push the stock through the bit.

Reset the jig and use the trim marks to cut grooves in the trim piece.

I use the RAS to cut the trim pieces slightly over sized.

and then dry fit them

Ran into a problem when I put glue on, joints swelled and fit was too tight. Broken one of the pins. Lesson learned – make joints a little looser for glue up and/or cut extra trim pieces.

So glue up round two:

Will sand down tails and trim to final length.

Next blog entry – cutting the tray front and back.

-- Shawn, I ask in order to learn

3 comments so far

View konaman's profile


82 posts in 3631 days

#1 posted 10-07-2011 06:44 PM

thanks for the blog on doing this.

View ratchet's profile


1391 posts in 3786 days

#2 posted 10-10-2011 07:07 PM

Excellent! Thanks for the tips.

View SPHinTampa's profile


567 posts in 3685 days

#3 posted 11-11-2011 07:16 PM

I created some confusion with my description of the templates. If you are going to cut double dovetails, you only need the double dovetail template (A thru D cuts), not a single dovetail template (A-B cuts) as well.

-- Shawn, I ask in order to learn

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