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Introducing Mr Mortising Jig

7K views 13 replies 10 participants last post by  Mike Gager 
#1 ·
I wish I could take complete credit for this, but it is really an adaptation of the jig Trap posted a while back which in turn was based on the MortisePal. I affectionately refer to this as Mr. Mortising Jig :)
The first pic is the Sketchup that I used for the build. The jig is essentially two 1 1/2" x 1 1/2" x 6" blocks joined together with a 1 1/4" x 1/2" x 6" template via 1/4" dowels. The dowels are glued into one of the blocks, the other block has a couple extra dowels that support the clamp which is pushed into the work piece with a 1/4-20 threaded rod to hold it into place. To prevent this block from slipping while clamping, there are a couple of nylon screws that hold the block to the dowels. These are not shown in the sketchup, but should be obvious in the pics. The dimensions were customized for my router table build where I am building with 1 1/4" lumber, but could easily be adapted for any width of stock.

I decided to try to make the mortise template myself. This took a bit of thought but really was not all that difficult. My plan was to cut 2" mortises, 1/2" wide. Using a 3/4" guide bushing, that works out to a 2 1/4" mortise centered on the 6" template. I used a couple of carefully placed stop blocks on the router table to cut the template on one edge of a 6" 1 x 4. This gave me a bit of room to work without hacking up my fingers :). I then cut the template to width on the TS.

I used a 1/2" spiral upcut bit to cut a 1" mortise taking about 3 1/2 passes :) ...the fourth pass was almost a lost cause because even with the upcut bit the waste starts to get in the way. After cleaning out the waste with the shop vac I made a final pass that cut very nice and clean.

Since I was planning on using loose tenon joinery I wanted to make sure that my mortises landed in the right places on all my lumber. The fourth pic shows my solution (sorry about the focus or lack thereof). I double sticky taped a carefully cut stop block flush with one end of the jig. This ensures that the jig can be seated on the end of the board at exactly the same location...sort of a built in story stick. After cutting all the mortises on one end of all the stock, I moved the block to the other end of the jig and cut the mortises for the other end. I did have a handful of mortises that were in the middle of the board and for these I used a carefully cut story stick to place them dead center.

The operation was a success and I am very pleased with the results. There are a few things I would do differently that I would like to pass on. I used a piece of red oak hard wood for the clamp figuring it would hold up to the metal screw...NOT. After about 70 mortises this is really getting chewed up...probably a good idea to epoxy a piece of metal or screw in a flat head screw to take the pressure off the wood. Another place where there is wear and tear are the dowels. Even the nylons screws when tightened sufficiently bite into the dowels pretty hard...probably better to use a metal rod here. But overall, a handy jig I would recommend to anyone looking to cut multiple repeatable mortises.
 

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#7 ·
Thanks everyone for the encouraging posts!

Dave,

I probably spent more time thinking about it than I did building it! Probably less than a couple hours to build. It took a few iterations to get the template the way I wanted it. Another tip for anyone considering this is to use a fence and stop block on the drill press to ensure your holes for the dowels are placed consistently on all parts.
 
#6 ·
Thanks for posting that. I think your Mr. Mortise jig will work perfectly for the patio furniture I plan to build. You should submit your idea to Shop Notes or one of the other woodworking magazines, there's probably a reward lurking out there someplace!
rstermer
 
#8 ·
Well I appreciate the sentiment, but as I said, this wasn't exactly my idea in the first place...maybe I just added a little dustmaker flavor to it :laugh:
If this thread helps you or anyone else, that is reward enough!
 
#11 ·
Thanks Bud,

Your version was the inspiration! It saved me some money and heck, I had some fun with it along the way.
 
#13 ·
Mike, you are very observant. There really isn't anything holding it other than friction. The dowels fit very tight and it does not move at all without considerable force. If this were not the case I would attach it to the block with a piece of double sided tape.
 
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