Massive Wood Joints With Chainsaw Mortiser

mortise-tenonOne common joinery method used in wood working is the mortise and tenon. A mortise is basically a hole in a piece of wood and the tenon is another piece of wood cut to tightly fit in that hole. The tenon is usually secured in place with either glue or a wooden pin or wedge.

The folks over at [WayOutWest] were building a fence and needed a way to cut a bunch of mortises in 4×4 inch posts to accept 2×6 inch rails. Although they had a chainsaw, trying to cut a mortise with it by hand turned out to be super dangerous because the chainsaw would kick up every time the tip of the blade touched the wood. The team had some parts kicking around so they made a fixture to hold the chainsaw as it is plunged into the 4×4’s.

The contraption’s frame is made from an old scaffolding stand and the slides are just pipes inside of pipes. The chainsaw is bolted to the slide and a lever moves it forward and back. A second lever moves the piece of wood getting mortised up and down so that the mortise can be cut to any width. This is a pretty ingenious build that only cost a little effort and will end up saving a bunch of time mortising countless fence posts.

21 thoughts on “Massive Wood Joints With Chainsaw Mortiser

  1. Why does it not have horizontal travel? Doing a bunch of plunges, then unclamping, moving, reclamping the post and then plunging a bunch more times seems silly. It should have plunged in then cut along the length of the mortise, in the usual chainsaw manner.

    1. Can’t help but think that an auger drill and a big chisel would actually be faster than this jig, with all the fiddling and clamping and setting up.

      The secret is to drill the holes from both sides to get them straight. With a bit of care you don’t really need any sort of jig.

      1. Can’t help but think that if they take that path we will miss the opportunity to learn something interesting, just saying that doing things in the “correct way” not always gives the community the best results, experimentation is the key to learning. And this page is “hack-a-day” not “wood-working-a-day” if you haven’t noticed.

        1. Aren’t you being a little selfish?

          If the dude needs an efficient way to make mortises, he could be better served doing it the old fashioned way, and unless they’re completely enamored with their new jig – they may just conclude that it wasn’t worth the effort in the end. It’s their invention for their purposes, and they have no responsibility towards any “community”.

          It’s curious how people sometimes try to own other people’s work by stuffing them under some label like “hacker” or “gamer” etc.

          >”And this page is “hack-a-day” not “wood-working-a-day” if you haven’t noticed.”

          So we can’t comment on how effective for its intended purpose a hack is?

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