Router Mortising Jig

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Project by hypnos posted 04-23-2010 04:49 PM 4028 views 12 times favorited 5 comments Add to Favorites Watch

This jig is a modified version of one found on American Woodworker – I added a height adjusting shelf and horizontal clamping to it so I wouldn’t have to mess with using shims at all. The dimensions are also slightly wider and deeper so it accepts stock a tiny bit bigger than the 3” wide and 4 1/2” deep dimensions from the article. The first picture shows the sacrificial bottom with a stop block (the piece to the left of the jig) that is inserted on top of the shelf and does not move when the adjustable height shelf is tightened.
I just bought this router about a month ago and I’ve never made a mortise before, plus I do not trust my ability (or rulers) to make easily repeatable and parallel mortises.
For these six coffee table legs I am making, I just had to find the center point on one leg, adjust the distance from the edge guide to the center of the bit, and adjust the stop blocks on top for the height of the mortise I wanted (it’s a 1” tall mortise and 1/2 inch wide – the same width as the spiral upcut bit I’m using), and I could cut them all after that with no measuring – just slide the leg in the back up to the stop block and tighten the clamps that go through the back wall…
All of the hardware can be found at Lowes, no such luck at Home Depot.
The last picture shows a couple legs with my first attempts at squaring the corners, it turned out great but a bit time consuming – it was my first time using my chisels I’ve had for a year too. I’m getting faster at that part though.

-- David P., Kansas City

5 comments so far

View DaddyZ's profile


2475 posts in 3519 days

#1 posted 04-23-2010 06:51 PM

Nice Jig !!

-- Pat - Worker of Wood, Collector of Tools, Father of one

View choppertoo's profile


304 posts in 3792 days

#2 posted 04-23-2010 06:53 PM

Great jig and something I’ve been meaning to make for myself. If the mortices are not through mortices have you thought about rounding off the tenons instead of squaring off all the mortices? Just something I saw Norm do once & thought I would try it when I had a mortice or six to do. Six of one or half dozen of another I suppose.

-- The greatest danger for most of us is not that our aim is too high and we miss it, but that our aim is too low and we reach it.. Michelangelo

View woody57's profile


650 posts in 3906 days

#3 posted 04-24-2010 11:57 PM

good job
I want to make one

-- Emmett, from Georgia

View bigike's profile


4057 posts in 3767 days

#4 posted 04-25-2010 12:24 AM

neat upgrades

-- Ike, Big Daddies Woodshop, http://[email protected]

View Beginningwoodworker's profile


13345 posts in 4152 days

#5 posted 04-22-2011 04:47 PM

Nice jig.

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