A reader asked if I cut the joinery before turning or after, thinking it would be difficult once the stock is round. I do cut it after, I bet you could do it lots of ways, but this is the way I’ve always done it, and with care you can get accurate joints this way. I learned some of these techniques way back with my predecessors at Plimoth Plantation, Joel Pontz and Ted Curtin. As always, it starts with careful layout. This seat rail is sitting in two “joiners’ saddles” – blocks with notches cut in them. I tend to position the stock with the growth rings running horizontally, this is probably over-kill. But it helps later on.
The reason the saddles are boosted up on that scrap board is because I’ve mis-placed my small square that I normally use to scribe the center plumb line across the end grain of this turning. I want the blade of the square right snug against the turning. Then I scribe a vertical line right through the center. Repeat on the other end.
These plumb centerlines become the basis for accurate tenon layout (same for mortises on the posts, actually). I scribe a line along the top of the turning connecting one end to the other. This line is only on the tenon, not along the seat rail itself. Then I can mark out from this centerline the thickness of the tenon – in this case 1/2″. Drop these down the end grain too. I highlighted these lines with a pencil so they show up.
Then it’s just a matter of cutting the shoulders and forming the tenon. I held it in the wooden bench hook, sawed with a backsaw. Careful to check that you’re coming down evenly. No need to hurry here.
Then I split the tenon cheeks. Once they’re both roughed out, check them with winding sticks so you know both tenons are in a plane. Then pare them flat.
Straight-grained ash splits like nobody’s business. Whatever that means…
Mortise layout is just the same. Then bore holes at the top and bottom end of the mortise. I use the square to help align the brace and bit. I have forsaken period accuracy for plain ol’ accuracy and am using auger bits instead of spoon bits. There’s 112 holes to be bored in this chair. One hundred and twelve. That’s a lot.
Chopping out between those holes is much like when we make hurdles with Plymouth CRAFT, just tighter tolerances. https://pfollansbee.wordpress.com/2015/10/11/riving-hewing-drawknife-at-plymouth-craft/
A finished mortise.
Pilgrim Hall’s web-page about their collection: http://www.pilgrimhall.org/ce_our_collection.htm