Mortise and Tenon Jig

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Review by John Little posted 10-05-2015 01:10 AM 3900 views 1 time favorited 3 comments Add to Favorites Watch
Mortise and Tenon Jig No-picture-s No-picture-s Click the pictures to enlarge them

I know this item has been around for some time but I could not find an LJ review of it so here goes. I recently purchased a Leigh Super FMT Mortise and Tenon Jig to use on an upcoming project building a stand up desk requiring a number of mortise and tenon joints. The Super FMT is the cheaper of the two FMT jigs Leigh makes but it works in exactly the same manner as the $1,000+ unit for about half the cost. It is still pricey but it does a fantastic job. The unit uses guides that are sized to the mortise and tenon you want. Both the tenon and the mortise are cut with a plunge router, that you supply, and they are both cut with the same setup. You simply clamp in the tenon work piece that you have marked with the center. Line it up with a sighting device that is provided and cut the tenon by following the guide. Takes 20 to 30 seconds max. You then unclamp the tenon and clamp in the mortise work piece with the center marked and using the same guide cut the mortise. If you have multiple joints to cut you can batch them and make the process faster. The precision is super as it is adjustable to .001 inch. The instruction booklet is easy to follow and has you up and running in no time. The Leigh web site has a number of videos that make it even easier. The unit allows you to work stock up to 3” thick and 5” wide by any length. The unit uses spiral straight bits from ¼” to ½” and the tenons and mortises are the thickness of the bit used. It allows for multiple tenons in many different configurations per joint. I am very happy with the jig and find it to be well made. I knocked it down a star because I find the F clamps used to secure the stock awkward to use. The more expensive model has a much better clamping system but not $500 better in my view.

-- John Little, ToyMakers of East Lake

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John Little

32 posts in 3328 days

3 comments so far

View Mikesawdust's profile


330 posts in 4124 days

#1 posted 10-05-2015 07:48 AM

I have the more expensive one, you are probably right about the difference not being worth the upgrade but I’m happy with it. The one bit I would add is to mount it high, I was constantly bending over to check the alignment. This will probably not be necessary if you use it enough but I’ve only used it on one project so far.

-- You never cut a piece to short, you are just prepping that piece for a future project

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John Little

32 posts in 3328 days

#2 posted 10-05-2015 01:28 PM

I agree with Mike that you need to mount it high, both for ease of use and to allow for long tenon work pieces. I built a box to attach it to that clamps to my bench top.

-- John Little, ToyMakers of East Lake

View helluvawreck's profile


32122 posts in 3951 days

#3 posted 10-05-2015 01:34 PM

Thanks for the nice review.

helluvawreck aka Charles

-- helluvawreck aka Charles,

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