Router Mortising Jig

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Project by hypnos posted 1553 days ago 3097 views 11 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


2375 posts in 1638 days

#1 posted 1553 days ago

Nice Jig !!

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

View choppertoo's profile


295 posts in 1910 days

#2 posted 1553 days ago

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


645 posts in 2024 days

#3 posted 1551 days ago

good job
I want to make one

-- Emmett, from Georgia

View bigike's profile


4031 posts in 1886 days

#4 posted 1551 days ago

neat upgrades

-- Ike, Big Daddies Woodshop,

View Beginningwoodworker's profile


13337 posts in 2270 days

#5 posted 1189 days ago

Nice jig.

-- CJIII Future cabinetmaker

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