Multiple Mortise and Tenon Joints
I’ve owned a Leigh dovetail jig since the early 90’s. I started with the 12” model that I used for drawer construction. I switched to the 24” model so that I could join the top of a case to the sides with a through dovetail joint. I bought the M2 multiple mortise and tenon attachment for the 24” D3 jig prior to building a book case that was to hold a tremendous amount of books. I wanted more glue surface and strength than a rabbet joint could provide and the multiple mortise and tenon joints provided that strength. These joints are not easy to produce; even with the jig. The tolerances necessary to achieve a joint of the correct tension require painstaking set-up of the jig. NOTE: My panels were too wide to run through my planer. I hand planed the panels flat and the thickness at the ends was not perfectly uniform. This caused me much grief when fitting the tenons. I should have run a sharp plane across the grain at the ends to try to achieve uniform thickness to a tight tolerance.
The Final Product
Watch this video to see how I incorporated multiple mortise and tenons and through dovetail joints into the Dr. White’s chest design.
Cut Mortises First
Watch this video to see how the multiple mortises are cut into the case sides. NOTE: I set my depth stop on my plunge router incorrectly on the left side panel and blew through the side on three of the mortises. OUCH!!! That was a 72” x 18” panel of glued-up and hand-planed cherry that already had the dovetails cut at the top. Thankfully, I hadn’t reset my dovetail jig fingers and was able to reproduce a new set of pins on the replacement panel. I was also able to recycle the wood into the vertical divider and one shelf within the cabinet. NOTE: I normally wear a dust mask when making such messy cuts, but didn’t for these videos. I realized later that I had a small vacuum attachment that might have caught a lot of the chips for the tenon cuts. I also recently purchased a more effective vacuum attachment for the dovetail jig, but it doesn’t work on the M2 attachment.
Cut Tenons Next
Watch this video to see how the multiple tenons are cut in the shelf pieces. I attached the jig to a shelf to raise it high enough off of the floor for the shelf piece to clear. I had already used this shelf to cut the through dovetail pins on the 72” case sides.
Close-Up of First Side of Tenons
Watch this video to see a close-up of the first side cut on the multiple tenons.
In the next blog entry, we’ll explore case construction and glue-up.
-- Mark, Florida