The (mortise) Jig is up!

Brent Dowell

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So, as part of my quest to finish my never ending table project, I've been working on a way to do the mortises in the legs. I've tried a couple of different methods to cut the mortises and have not been happy with the results.

So, Time to try another method!

I've got a copy of Carol Reeds router book and it has a really nice looking little jig, so I put one together.

But my mortises are of a little odd size, so that one pass with a router bit would not get it done. So I also put together an adjustable router template.

I figure I'll use a router collar with the template to get the mortise cut halfway through, then use a bottome bearing pattern bit to get it from the other side. Then I'll clean up the corners with a chisel. That's the plan anyway.

So here are the pictures.

mortise_jig_1.jpg

mortise_jig_2.jpg
mortise_jig_3.jpg
 
I've been looking at it and while I'm happy with how the base from carols book turned out, I think I need to rework that adjustable template.

The t-track I used is exactly 3/4" wide, but the ply I used was not. So my hack was to use the thin ply to make a smooth surface for the router to ride on.

I think I'll pull some straight grained poplar out of the pile tomorrow and rework that template. Shouldnt take much time, and I'll be happier with it.
 
Now had you completed the jig with the plexy and tape you would not need your attachment.

That jig turns a router into a milling machine if you do it complete. 😊

Very cool jig.

Even though i now have a really nice router table, there is a lot to be said for something fundamental to that jig, inverting the router let's one see what is going on, on a router table that would be hidden and shavings trapped.

Of course there is always the good old sharp mortise chisel. ;)
 
Well, There are a few reasons I'm putting this together. The legs on the table 3" thick of Hard maple with through mortises.

I have tried:
1) My hollow chisel mortiser.
The largest bit I have for it is 3/4", My mortise is 1" wide. So I'd have to make multiple passes.
I tried using it on this wood and it had a very hard time punching a square hole through the wood.
So while I might use that on other woods and projects, it's just not much better than Drilling and using a chisel.
2) Hogging out the waste and using a chisel.
I used this method for cutting the mortises where the legs go into the aprons. While it did work,
I don't feel confident enough in my ability to do the next 6 mortises and have an acceptable level of quality.
It also took a LOT of sharpening.
3) Fixed Router template made of Plexi
So, I could have just created some router templates out of plexi, or ply and that would probably work just fine.
I'd also have to rig up some kind of way to hold the template to the workpiece, and double faced tape would work.
But then I'd end up with more half assed templates and things laying around the shop that only had one use that
a few years from now I'd have to throw away.

So thats why I built this jig. It really holds the workpiece and the template solid. I'll also be able to create a base plate as described in Carols book and use it the way She had intended.

At any rate, Like I said, I wasn't happy with the adjustable template I made, So I got a piece of maple and milled it up this morning and re-did it.

I also swapped out my aluminum miter slot extrusion for a standard T-Track. This gave me a more solid way of holding the template to the jig.

The workpiece can just easily slide in and out from under the template off the to the side and butt's up against a solid stop. That way I can guarantee that my mortises will all be in the correct spots as I go through and cut them.

mapleAdjustableJig.jpg
 
Well, I do believe this might just work. Found a scrap of maple and gave it a test.

Drilled out the center with a spade bit then Went part way down from the top with a router collar.

Then took it out, put it in a vise and cleared out from the other end with a bottom bearing bit.

A little burning on the corners, but it's hidden so not a huge deal.

Gave it a half hearted attempt to square it up and I'll be darned if it didn't clear it out pretty easy.

I think this will work.

testmortise.jpgtestmortisesquare.jpg
 
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