Killing a Tenon and Upside down Mortise


I’m down at my Grandfather’s house hanging some security doors on his deck. And, being the optimistic fellow that I am, was able to explain the benefits of using a bit of honest joinery to add a post for the hinge rail of the door. The main sill beam of the wall had been cantilevered out to support the eave beam at the edge of the roof, but it was a bit under sized to the task and managed to noticeably sag over a couple of decades. So, time to jack the beam up and slip a post in!

I had to cut the mortise upside down, very different experience. All the swarf wanted to drop right out of the mortise, which was nice, but then most of it managed to head for my eyes.


Beam with centerlines drawn, and tenon cut and killed with a hammer.  I read recently in “The Complete Japanese Joinery” about the joinery for shikii and kamoi, the grooved sill and header boards which serve as the track for fusuma and shoji in traditional Japanese homes. Because they are installed after the posts are erected they must use some creative joinery to allow their secure installation. The most simple joinery involves a mortise on one side and toe nailing the other, which is basically what was employed here.


Assembly was easy, the compression from hammering the tenon surfaces coupled with the sheer weight of the roof made seating the tenon a breeze. Plus it was only really a stub tenon. I put two screws through to lock the tenon, but its not like the roof is going anywhere that it hasn’t in the past fifty years. Could hold up a beer bottle!


Ok, setting a post is not a big deal, but is really out of the norm for the work I’ve done professionally as a carpenter. Normal would be butt joints and you screw that sum b**ch in there and get on with it. It made a work day very fun!


My plane iron did this on the stone, very cool! Couldn’t get it to stick twice though. It really looks like it shouldn’t be able to stick like that.


I’ve done a fair amount of work on this house in the past, including cutting the scallops on the beam edges with a chainsaw. Cutting one beam end up on a ladder with a power tool like that is fun, but thirty? That just starts to feel like work.

I like hanging doors though, it takes a lot of consideration for all of the plumb surfaces involved to do it well. All this needs is a bit of paint for the post and the corner boards and it’ll be on to the next one.

Hip roof joinery, here I come!

2 thoughts on “Killing a Tenon and Upside down Mortise”

  1. holds a beer, lol

    Looks like a nice hammer that one. I was doing the killing of the tenon for the frame, the wood managed to compress around 2mm or so, I wonder if it expanded once I glued it.

    Looking forward to see your struggle with those angles mate.

    1. Thanks! It will be the good kind of struggle, hip roof angles. I relish the challenge, and thankfully have the time to study it out pretty well.

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