More shaving, some steam bending, and finishing up with some assembly.
The day started out with shaving more octagonal rungs for the front of our chairs. However we quickly moved into cleaning up front posts and shaving down the front rails the hickory bark will be woven into. With the goal of ending the day with our chair fronts assembled, Andy had us focus on ensuring we had enough glue-ready parts (1 hickory rail and 2 red oak rungs) by the end of the day.
Rails
To handle the extra stress imposed by the seat and the likelihood someone will stand on the chair rails, the rails were split out of hickory not red oak. Why not make the entire chair out of hickory if it’s stronger than oak? Because it’s a huge pain in the ass to shave. Hickory certainly is strong, but I could have shaved 2 or 3 oak rungs in the time it took me to shave the hickory rail.
The hickory rails were already oval shaped and cut to length for us. We only had to shave the tenon close to it’s final 5/8″ size so it could be run through the tenon cutter. Once the tenons were formed, we removed/feathered the excess material leading up to the tenon so there wouldn’t be any shoulder. We began with the drawknife, removing material carefully so that we wouldn’t remove any from the tenon on accident. Once we reached the point of diminishing returns with the drawknife, we switched over to the spokeshave, rounding out all the sharp-ish edges. Since the rail would hold the hickory bark seat, we don’t want any sharp edges that might dig into the hickory bark.
Front Post clean-up
After having given the front posts a day or two to dry their exterior some, we worked on getting them glue-up ready. That started by straightening and evening up all the lines on the 8 faces of the post. We used a spokeshave and block plane set to take a light cut to get facets as even and straight as we could on the legs. While mine still had some bend to the legs and low spots on the faces I couldn’t even out, I was pretty happy with how they turned out.
Lunch break and history lesson
Again one of the unexpected treats of this course came not from making anything but from learning something new. Andy gave us a quick history lesson via slide-show of various ladder back chairs in the Appalachian style. We heard about makers both long ago and modern that have contributed to the world of ladder back chairs. It was fascinating to hear about the evolution of these chairs through the years as well as Andy’s thoughts on where they might be headed.
Steam Bending the slats and back posts
At some point in the afternoon, we broke from shaving to go do some steam bending. This chair has 3 slats (~3.75″ x 3/8″) and 2 back posts (bent near the middle slat) that all have to be steam bent. The rule of thumb found in a lot of literature regarding steam bending, is that wood needs to steam for 1 hour per inch of thickness. Andy said he found this to be far to short and usually went up to twice or three times as long for his bends. He said the extra time helps get everything limbered up and while there can be issues with burning if you left parts in the steam box too long, he had yet to encounter that.
Bending Slats
Split out to start with quarter-sawn stock before getting band-sawn then run through a planer for final thicknessing (to 3/8″). The slats are thin enough that they shouldn’t require much effort to bend. The process:
- After carefully removing from the steam box, the slats get slowly bent over the form by hand. First they are bent backwards i.e. the side that will eventually face out, gets bent so that it is on the inside of the curve.
- After it is slowly bent backwards, we flipped the part around and bent it over the form in its final configuration holding it there for 30 seconds or so.
- Move the bent part to the drying rack (fit it into the drying rack by hand if you can)
For Andy’s chairs, he just bends it by hand and holds it there for a few seconds before transferring it to his drying rack. The part didn’t stay bent during the transition, so you have to muscle the slat into the drying rack or clamp the concave side of the slat to a curved wooden block to ease it into the rack. The parts can stay here a couple of days. You want the slats to be dry enough to retain the curve but not so dry that you can’t manipulate the over bend back out of them.
Bending the Back Legs
Also after carefully removing 2 back legs from the steam box (they steamed for close to 3 hours), the legs were driven into the bending form, making sure the tops of the legs were wedged in all the way (not wedging them in all the way will end up with back legs that are bent at different locations. This job was best done by two people, one would line the legs up and stand-by with the clamp while the second one would slowly bend the legs in to the form (if only 1 person could be present for the bends, Andy recommended using a squeeze-type clamp that could pull the legs together). Once the legs were carefully bent, some cauls were held in place while the first person clamped the legs over the cauls. Out of the 6 legs we bent (3 sets), only 1 leg hand any evidence of fiber failure on the outside of the grain. I was pretty impressed considering the thickness of the legs. Even in the case of the 1 failure, the fibers lifting away from the bend did not go very deep so the leg might be salvageable.
Mortising the Front Posts and Assembly
After the steam bending, we went to work getting our fronts ready for assembly. Andy gave us a primer on how to orient your posts for maximum efficiency of wood movement. The short version is, you want to orient the growth rings of all 4 posts as if they were still in the tree and the pith is in the middle of the seat.
Once identified, we marked a line on the top of each from one to the other that represented which side the rail and rungs would be mortised into on both. We also drew a “F” or wrote the word “front” on the face that would be facing outward. Documentation and organization help a lot when it comes time to glue. The line of the top of the legs was carried straight down the leg, running through the middle of the face. We used the story stick to layout the mortise location, using the bottom of the foot as the reference point.
The mortising was done with a 5/8″ brad point on a drill press with the goal being a mortise slightly deeper than 1″ into the front post. Since everyone’s legs were slightly different in width we couldn’t trust a depth stop on the drill press. Instead, we drew a line on the drill bit at 1″ then drilled down until we couldn’t see the line. We also drilled a test hole at the top of the post, in excess material, to ensure our mortise depth was accurate.
Once we had the mortises complete, we were ready to assemble. We did some final marking on the rungs and rail to ensure everything glued up in the correct orientation (I marked the outside face on all my parts with blue tape). The fat side of the hickory rail should face inward and just slightly down. Using a partner to help glue and verify assembly depth, we took turns gluing things together. One person applied glue to the tenons, the other applied glue to the mortise. Once ready, the chair part owner would drive the three tenons fully into one post. Then using the partner to help line things up, drive the post with the tenons wedged in, into the post with none. Once they stopped moving, you were set.
Verify the assembly is straight by using a tape measure or rule to measure the distance between the posts at the top rail and the bottom rung. Ideally they should be 15.5″ apart in both locations but as long as they are both the same distance (to 1/16″) and close to 15.5″, everything will work out fine. Also, counter any twist with hand pressure and/or vise assisted counter-twisting. You want the front assembly to sit flat on the bench.
After another long but fun day, take a moment to appreciate everything you got to work on today.