The historical record is pretty clear. When it comes to chair joinery in vernacular furniture, most of the tenons and mortises are cylindrical. The most likely reason for this is you need only simple tools: a brace and bit to make the mortise, and a handplane to make the tenon. (You could also use a hollow auger, a lathe or several other methods to make the tenon. But using a plane is the simplest approach.)
To make a tapered joint, you need a reamer to enlarge the mortise to the correct shape. The tenon can be made simply with a plane. (Or you can speed up the process with a specialty tenon cutter, a lathe or other gizmos.)
Reamers show up in the historical record as a shop-made tool or something manufactured by a blacksmith or other metalworker. But they aren’t terribly common.
When I first started making chairs about 2003, I didn’t own a reamer. So I made all my tenons cylindrical. It’s fast. And when done properly, the joint is strong.
Chris Williams and I have long debated the merits of tapered joints vs. cylindrical ones. In the end, the reason I used the tapered joint in “The Anarchist’s Design Book” (and teach the method) is because it is more forgiving.
When you bore a cylindrical mortise, there is no way to fix an error in your angle. You are stuck with the result, like it or not.
When you ream a mortise, you can adjust a mortise that’s even 10° off (I’ve done it). That is reason enough to ream for me. And the extra expense of the reamer is more than justified.
We could spill endless pixels comparing cylindrical or tapered joints, pros and cons, strengths and weaknesses. But in the end, I ream for forgiveness.
— Christopher Schwarz
The Mortise and Tenon: Ream’agined. Coming to a chair near me 😀
Excuse me for plugging hand-powered reamers. I was too aggressive with a powered reamer, but the manual variety are more forgiving, and still very fast. A couple of turns with a little pressure can realign a leg tenon pretty quick. I have one made by Tim Manney, and it’s a wonderful tool.
Does it work in white oak?
Beats the heck out of me. Only a sadist would make chair seats in white oak.
I saddled my seat in White Oak during the recent chair making class at the Florida school of woodworking with Christopher Schwarz I learned a lot and came home with a successful chair.
They’re better in soft woods. Just broke one that I made about 12 or so years ago because I was trying to make a matching homemade tenon cutter out of hard maple. They work well in pine though.
No worries Chris. Apology accepted.
A few weeks ago I made my first attempt at the staked saw bench from the Design Book. I am less than I novice woodworker, but I had a fantastic learning experience. The legs are all wonky, but the stool is solid. I only wish that I knew where my mistakes were made. My guess is with the tenons given that I found the first three tenons to be a real challenge. I thank that the fourth one was better.
I made a reamer about 5 years ago and the made a taper that matched the reamer. works great, the only problem is I have been having a hard time steering it. I drilled the hole at the right angle (1 in 4) then when I reamed the whole it finished up darn near 90 deg. never had a problem when I was making milking stools. so my first welsh stick chair has legs that are close to straight up and down. It’s great for leaning back and balancing on the rear legs but scary to just sit in. any help on the reaming?
Hi Rachel,
I’ve only used shop-made reamers a few times, so I’m no expert. I use a bevel to guide me, but I know that lots of other woodworkers use lasers, which seems to help. Also, check out Peter Galbert’s IG feed. He recently showed a way to improve shopmade reamers with some PVC to guide them. Very ingenious!
wow thanks I think that will do the trick. so simple.
Hi Rachael
Chris S. No-Fear Chairmaking video will give you all the information you need to layout the chair legs and properly ream the legs at the proper compound angle. I purchased a DVD at
https://desertoutlets.com/ or you can veiw the video online at Popular Woodworking after paying their fee.
For me the key thing that helps accurate reaming is having a piece of dowel with the correct taper on the end, so I can regularly withdraw the reamer and insert the dowel to see how I’m doing against the bevel and sightline (you can’t use the leg if it’s tapered, as it’s misleading to the eye).
The reamer can help correct problems, but it can also take you wildly off course very quickly if you don’t check your alignment frequently.
I have an old reamer that was probably made about 1780. It is a 6″ length of steel with a square section and tapers along its length. It scrapes rather than cuts so takes a bit of effort but it works. I suspect my Grandfather used it to align the draw holes to secure mortise and tenon joints with a tapered dowel.
That suggests hairshirts and flogging, for some reason. And I DEFINITELY don’t want to hear the details.