Saturday, May 26, 2018

Curtis Buchanan Sackback Day 7

It's May in Jonesborough, TN, USA. Big downpours of rain can last for 5 minutes or 5 hours, depending. We woke today to the latter amount of rain and Rob was kind enuough to swing by my cottage and pick me up to get to curtis' shop without running through old town with a garbage sack raincoat improvisation.

Luckily we started the day with more spindle work to get these things in their final tune. I needed some mule work to warm up with. For the sack back chair, we have 3 intersections to nail with the spindles where they hit the seat, the armrail, and the crest rail. you get real close using test offcuts that have been drilled using the bits you used for the attaching pieces. There's a system for this that Curtis uses and it's really helpful. I don't want to do anything but make spindles for the rest of my life. I'll wear a monk's habit and take a vow.

here we're using a rat's tail file to define the taper of the bores of the hand rail that the spindles have been tuned for using an offcut
Next up was to get the crest rail joined to the hand rail. yep, more hot angular drilling action was in play using sightlines in two directions, and two comrades to spot your angle of approach.
because the crest rail is perfectly tapered from the tapering system that we applied on tuesday, we use reamers used for cello tuning knobs (i think) to orient the hoop in the right direction. you are considering a multitude of factors when doing this involving forwared/reverse/twist. These reamers are amazing in their effect. just a few shavings will give a measurable impact.
Here's a mistake i made. I was trying to bandsaw off the waste of the handles, and managed to bump the opposite side while pulling out of the cut to relieve it from another angle and it cut into that very important outer radius. well. i had to shake that one off. Mark had the right idea to just scab on a piece and redo the cut. I'll do that, but i wont be doing any more bandsawing today.
There's a systematic way of "winging it" in this workshop. you reduce your problem to a few known sight lines and then set forth with your drill. it worked well for me here. Curtis emphasizes all the marginal things you can do to arrive on time with a piece. Get your angles as well as possible from the start and you don't have to oversteer when you get close. I love this approach because it makes sense to me and how i live my small life.
Rob lives in Nevada, me in Californication. We're not doing the full glue up of our chairs, but we watch and take notes from a "live" glue up. I noticed this during the undercarriage assembly exercise that curtis understands the anxiety of anticipation and somehow is able to subdue it with a warming drape of reassurance. You're good here. You wont encounter something that can't be fixed.

we won't test this observation today, since Mark's chair went together so beautifully. Curtis coached us through the glue up and it works. we just paused to take in what had occurred. A bunch of wet, wild wood was dimensioned to make a beautiful, refined piece. These chairs are "built like a tank" as curtis says. but they are so damned gossamer and light. My phrase? TITANIUM GRANDMA HUG.

arm rests from maple are pre-kerfed, but the lower spindles are cut insitu with a chisel

I finally got the outermost upper spindle holes drilled after a bit of courage (you aim in a way that makes sense but requires a bit of controlled 'winging it'. i'm happy. this chair will welcome sarah and me to the desk in our guest bedroom/library. it's a gossamer hug from TITANIUM GRANDMA. this chair is stronger than you'd think because it's derived from straight grained white oak and maple. it's the chair to use as a shield for getting out of a bar browl. it is a chair to hide under in an earthquake. it's a chair that i hope to die in if it's not the bed i made. (presuming there will be any remains when i die).
Rob and I went to a U-Haul outlet to get some packing material for return to our homes. We got a small wardrobe style box and cut it down and used some bubble wrap and extra cardboard to hopefully provide safe passage for assembly on our return. I'm just fitting my chair here, it will be layered in oak shavings and bubble wrap and a few prayers.

I hope to post a final assembly when i get home.

Friday, May 25, 2018

Curtis Buchanan Sackback Day 6

Six down, one to go. Today we worked on joining the arm rail to the seat. There's a tricky amount of geometry to figure out while reducing the organic geometry that this chair consists of, to angles that one can measure and/or drill a hole to. What is surprising is how well these tricks work at getting your joints to mesh up okay with one-another.

after a bit of spindle warm-up, we progressed to the arm rails. We pulled them from the jigs where they were drying in a kiln and cleaned them up a bit with planes, spokeshaves, card scrapers, sand paper, and Frank Zappa.
A bit of stuff happened and PRESTO
Here's Mark's, ready for take-off.
Rob is just off the lower spindle shaving ablutions and is seating his arm rail. all the chairs are looking good from here. the beautiful angles are hard to achieve in the shop, but that's what makes a comfortable chair. We did 11 hours today 8-7:30 with a small break for lunch. We're engrossed in the work even though it's hard.

Curtis Buchanan Sackback Day 5

I walk 10 minutes from the cottage i am staying to where i'll meet up with mark and rob on a new adventure in curtis' workshop. none of us really knows what's next; we're all kind of 110% engaged in just keeping up with the present, hanging onto a rail with our legs dangling out the side
Curtis is making the same sackback chair along with us and many of the lessons begin with him talking through what we'll be doing, and then demonstrating on his chair, with some elaboration carried out on a chalkboard if need be (his ingenious kiln cabinet houses racks for chair parts to dry out but its doors are chalkboards for sketching details on). He carries through a sequence and then we try to execute this sequence.

Well, today involved a lot of sketching, and a lot of doing. We're assembling the undercarriage of our chairs from carefully fitted parts, joining in a complex sequence made as simple as possible.

This involves taking care to mark your pieces in a way that leaves no doubt about how things go together when the clock is ticking. It also involves very practical ways to measure these odd angles using as simple of layout tools as is possible.

In a small class of 3 students, we acted as a team. The undercarriage assembly could be broken down into 3 major stanzas. First, layout and angle measurement. here we each measured our angles on all the joints, recorded them and marked them on our pieces as instructed. We then each checked each-other's work, and checked, and re-checked. I don't think we found any errors in our markings, but it was really confidence boosting to have someone else give a once-over after all the work put into the parts. It's like anything important in life, and it vests each of us in each other's work.

Secondly, we all drilled out our joints using the ingenious alignment system that Curtis had set up. There are many ways to skin this cat but with a small team of 3, one person could verify your angle bevel's setup while another helped you with getting your drill plumb.

Finally, glue up. any woodworker can relate to how anxious this can be. having 2 other comrades to see something you missed is invaluable. and i remember at least 2 instances where my team helped me with something i got reversed or a glue tenon i missed. I was so thankful having Mark and Rob there to watch over me and i was also invested in their pieces going together.

I have Essential Tremor (ET), which is an inherited neurological quirk where my brain's signals to my hands are scrambled just a bit, and it gets worse when i get tense, such as while doing unfamiliar work in front of people. Today I literally had to brace my right hand with my left while applying glue to a mortise in order to avert glue spattering all over the bench! Rob and Mark were particularly helpful while i struggled. Canadian woodworker Stumpy Nubs has the same deal, and recently shared a video regarding his challenges with the condition.

At the end of the afternoon, we all had successful undercarriages put together in a time-tested way. It was a hard day with a lot of uncomfortable learning to do and i think we each gained a lot from having our boundaries expanded.
Oh, and let there be no mistake, any moment of downtime you'd be damned sure we were out on our shaving horses taking these once ripe chunks of white oak down to a gossamer, athletic spindles to support the backs for years beyond our own time! Here I am simulating my future self's pubic hairs.
A particularly handsome planter i saw on our walk to pizza and beer after today's work.

Thursday, May 24, 2018

Curtis Buchanan Sackback Day 4

Well, today involved a lot of learning about carving a recess into real pine. You are dealing with grain at a very practical level when digging out a recess. There will be places where the grain runs away from your edge, where it runs into your edge, and the slack tide between the two. We are working with a shaping tool called a travisher. It's a graceful tool and delivers a very gorgeous surface off the blade, when you have it tuned properly.

We learn about how to control the cut, skewing left or right, when to swoop in or out. Pine is soft, which makes it fairly easy to cut, but also the fibers will tear out unforgivably if you are not paying attention. Curtis has a library of travishers to work with and we tried them all.

One plane that i Really LIKED was a "heal shave" used for boots at one point in our history. It has a fairly aggressive dish to the blade and an openness to the cutter that makes it really useful for situations where you really want to see what your cutting into. This particular model is a Snell and Atherton with I think it's handles removed.
Some hours later we had our seats dished out pretty well, and now they needed to be cleaned up using a scraper, and then sand paper to 150grit where applicable.
Curtis demoed his card scraper sharpening magic to us at his bench. and, NO IT IS NOT MAGIC. It's a very practical way to get 'er done and keep going with the work.
I periodically checked my seat's front curve using this trick from my fiberglass plug building days to see the angles off a tangent. It was useful when looking for symmetry between both sides of my seat's pummel, but also to compare to what curtis did with his.
And then there was the fun part of going to town on the underside of the seat to lighten up the look of the front. Most of this work is achieved with a draw knife, followed by a finely set spoke shave to clean up parts.
Oh, and yeah, if you were waiting around for something to do while stuffing tomato custard pie into your gob for lunch, you were refining your spindles.

Tuesday, May 22, 2018

Curtis Buchanan Sackback Day 3

Here's an extract of pine relieved from the groove delineating the spindle deck of the seat from the dished part receiving future, hopefully grateful, asses.
Today we started in earnest upon boring holes into this gorgeous pine. Next to the scent of fresh white oak shavings, this pine tingles my spine with delight. I can't tell which i like better, it's usually what's not been on the scene for an hour or two.

Now, I am not the guy to delve into the geometry that's going on here, but i will try to share a few parts. Hardest part about drilling a hole is going in at the angle you intended. this includes 90deg, of course! But none of the angles here are anywhere close to that figure. So the layout lines designed into this piece are meant to assist you with visual cues on how to guide your drill bit at the correct orientation. A concept of "resultant angle" helps reduce this into solving the problem as simple as is possible. just google it.

probably the most unusual tool in this kit is the reamer, which is the wooden tapered implement seen in the field below having a metal cutting edge (harvested from a hole saw i gather?) that floats in a kerf along the axis of rotation. It's a 3 degree angle off axis, and you can use this to figure out what angle to set your tapered bores at, with really good accuracy. None of us students had used this method before so it took a lot of checking, and rechecking of our bevel guages and trepidatious steps into the pine. What's great is that curtis has designed this process to allow for correction if you don't nail an angle right. the taper boring tools allow for course corrections if you're a bit off. YOu will apply cutting pressure towards the direction that you want to aim for. with tapers this is possible. It would not be possible with straight tennons.

Once the leg and major arm rail holes were bored, we were ready to do some preliminary shaping of the seat. We start with a very unusual instrument called the adze. It's the tool you see on the left of the seat piece curved along the throw and the striking plane. It cleaves large chips from the pine in one throw, once you get the hang of it. it's obvious you have to be careful with this tool. know where your supporting hand is and where your knees are. But honestly, you dont really apply any force to the cut. when done right, the mass of the adze head does exactly what you want, and it chips out the waste.

for pine, it's kind of overkill because it's such a soft wood. Regardless, it saves work for Act II "The Scorp"

THis was my first time using a scorp. it's essentially a drawkife that has been bent into a "U" shape. I love this tool despite not having been able to really do good work with it, i watched Curtis relieve his seat using it with a grace and sweeping action that is breathtaking. A scorp will teach you rather strictly about grain direction and how to slice through the grain to maintain an angle of incidence that produces clean cuts. Too high and you don't cut anything. Too low and you start to dive into the grain.
We then do what i think is the most important cuts to define the leading edge of the seat. You dive down and then sweep up in a curve that is lobed towards the outside and points gradually to the topmost point (I think this is also called the "pummel"). what better instrument to deliver this shape than the draw knife! use it bevel down for agility and angle the blade for a skew cut. go big on this one.
I'm not quite there yet but close. I need to shave to make the leading edge of either side of the pummel a little less blunt. That's important for aesthetic reasons but also ergonomic ones as having a blunt nose here i think would be uncomfortable on the hamstrings...

that's all today. tomorrow will be new territory in the travisher and who knows what.

Monday, May 21, 2018

Curtis Buchanan Sackback Day 2

Today's agenda involved crest rails and arm rails. another full day of riving, and draw-knifing at the shaving horse, followed by steam bending of these pieces to their final curved shape. I don't think any of us students had done steam bending, and it comes on at the end of the day after putting all this work into making as best we could pieces of continuous grain dimensioned to the appropriate shape for the process.

This morning we jump in the deep end with riving the longer rails. It's different than riving spindles as there is more than twice the distance to split and you must be open to the feedback that the wood is giving you. I managed to catch this sequence of photos of curtis riving out 2 armrails from one blank. Notice how he's placed the "heavier" piece towards him in the brake. the froe's handle is always turned towards him to encourage the split to move more towards the heavy side and keep the split dividing the pieces evenly.

here's a good trick i tried to capture, but not as clearly as i would like. Curtis is using the non-froe hand to pinch the lighter side towards the heavier one. This also helps prevent the split from wandering. also notice how he's standing on the edges of the brake boards. This is an activity that develops head to hand, to foot coordination.
And here are the roughed out pieces cut to length and ready for the shaving horse. Once again, we work the radial plane to continuous grain surface, then a tangential plane, scribe to thickness on opposing sides, and repeat.
I'm trying to capture here what it's like to pull a drawknife with the grain. As a cabinet woodworker primarily, i'm used to dimensioning stock to machine flatness and squareness on all sides. You need to just put that thought away at the shave horse. Here, your strongest wood runs with the grain whereever it wanders. This reduces the chances of grain "runout" which will not work in a bent piece like a crest rail. You need the grain continuous thorughout the piece and rely on the steaming process to bend the piece into shape.

So here, i've found using less hand force to pull the drawknife through helps me. I try to relax my hands. even take a deep breath and exhale while working with the pull strokes. I know that sounds corny, but it is helpful!

Here's the crest rail taken down to square thickness.
Next is to produce an octagonal cross section, that narrows to a 3/8" at the tips. Curtis has a great, great trick to make that happen.
finally we get to apply spoke shaves to this piece to make it round-ish. You then decide on the best direction to bend this guy into a "U" shape. It's not obvious what the best way is to bend it considering the radial and tangential planes. then there's the natural bend of the grain expressed in the wood. Here you see a crest rail that had been bent from some earlier project in curtis' studio. We used a plywood jig which will be shown below to create the bends.
I unfortunately was too engrossed in the process of making the arm rails to take a photo. It was very intense and i made a few mistakes that curtis was able to advise on how to correct and we got them done.

Regardless, let us proceed to late in the day with STEAM BENDING!!!! THis is Curtis' steaming rig, a plywood enclosure wiht a pair of Wagner Power Steamers hooked in.

I know the expression is usually used in the complimentary side, but today, this was my FIRST RODEO in steam bending! It is a very sober environment when this process ensues. You have very hot steam, a small timeframe for applying your bends, and all of the forming jigs and attendant wedges/pegs need to be mise en place.

What is great about the experience is that you have a couple other equally vested students to help you drive the pegs and wedges into place. Curtis was there, but like a great teacher, I think he just instinctively knew to let us execute most of the bending work with our own hands, after demonstrating the process to us himself. Good teachers know when to step in and apply some reinforcement, and when to just step aside and let us learn.

We all came through on the other side with rails that are well serviceable and can continue tomorrow into the next phase of the process.
While we were steaming our rails, we layed out our seat blanks using Curtis's drawings. these are produced by a draftsman that Curtis works with. and they are full scale on mylar (i think that's the material).

Now, there are about 8 million things to keep in mind when laying out a seat: which way the grain is running, which way the bark side faces, which way the cathedrals point, grain direction at the locus of the pummel. these are some intimidatingly gorgeous full thickness slabs of pine that Curtis has arranged for us students to work with.

I will do my best and be thankful that i've been presented with a piece of pine wider than anything i've ever seen milled.

Both Curtis and Student Mark have worked in house carpentry. Today's fun fact was a carpenter's trick for laying out a perfect circle with a steel carpenter's square, using two nails. Can you guess how this was layed out?