How to fix crooked mortise and tenon?

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Forum topic by notdan posted 12-07-2014 04:41 AM 1427 views 0 times favorited 6 replies Add to Favorites Watch
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22 posts in 802 days

12-07-2014 04:41 AM

Topic tags/keywords: mortise tenon hand tools

I made 2 mortise and tenon joints with hand tools (chisel and saw) today for a work bench leg+stretcher. Once assembled, on both of them the stretcher angles ‘in’ (to where the middle of the work bench would be) rather than being square in line with the leg. I’m not sure if the problem is with the mortise or tenon or how to tell.

1) How can I fix this?
2) Any tips for not doing it again?

The tenon is 1/2” thick, 4” wide, and 2” deep.

6 replies so far

View ElChe's profile


630 posts in 755 days

#1 posted 12-07-2014 04:54 AM

Does the tenon look good? If it is at an angle you should be able to tell just visually. With the mortise you can mallet in some wood with glue and have at it again. I suspect the mortise got cut at a slight angle? I use a flat block to register my chisel so I know that my chisel is at 90 degrees. Take a pic of the tenon.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

View notdan's profile


22 posts in 802 days

#2 posted 12-08-2014 02:26 AM

Spent some more time with this today. The mortise was actually pretty good, but the tenon was embarrassingly bad in just about every way. Got it cleaned up with a chisel and I think it’ll do (a little loose now but I can probably fix that). Did another one paying much more attention to keeping the tenon square and it turned out much better. Have done about 4 of these joints in my life so still learning :)

One thing I’m still having problems with… when I cut the tenon and it a bit too tight to fit the mortise how do I easily trim it down? I’ve seen people do it with a router plane but I don’t have one (yet.. should I just buy one?) Right now I pare it down to the marking line with a chisel, then pare it some more and more until it fits. But this takes a long time. Is there a better way?

View ElChe's profile


630 posts in 755 days

#3 posted 12-08-2014 03:30 AM

A rabbett block plane lets you cut cross grain to reduce the thickness of a tenon. But they can be pricey. Mine is a Lie Nielsen and I gave up a first born ($160) for that one. I suppose a router plane would theoretically work depending on length of tenon but I’d be concerned about tear out. I use the rabbett block plane. I guard it with my chihuahua’s life. Can’t afford to replace either.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

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3969 posts in 1770 days

#4 posted 12-08-2014 04:41 AM

Glue a thin slice of wood onto the the tenon, then adjust for a tight fit.

-- Bondo Gaposis

View waho6o9's profile


7118 posts in 1996 days

#5 posted 12-08-2014 05:19 AM

A big ol flat file works wonders.

View MrRon's profile


3891 posts in 2662 days

#6 posted 12-10-2014 04:56 PM

Bondogaposis and Waho6o9 is the way I would go. Woodworking is 50% doing and 50% fixing. Rarely does it go 100% well the first time.

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