Intro: Rockin' Stump
Having enjoyed many a fine fire in my day while perched on a stump, I well know the difference between a seat and a chair. A stump is a seat. A chair has a backrest. In making a fire, one has taken the first step in a concerted effort to chill the %$#@ out. Pulling up a seat can only undermine this endeavor. A stump has the right essence for the job; it has the right aesthetic and feel; it bears the perfect material relationship to the fire itself; but it lacks the key ingredient of reclination. For this reason, I have taken to making stump chairs.
With this project, I envisioned a stump chair so potent as to enable chilling the %$#@ out even in the absence of a fire. I envisioned a stump chair that defies the blocky discomfort of its own stumpness. I envisioned stump technology not stepping, but leaping forward towards a glorious future. Thus was born, the Rockin' Stump
Step 1: Runners
As it turns out, "runners" is the word for the curved pieces underneath a rocking chair. (I just learned that from the interwebz). For no good reason, I had taken to calling them sleds (though sleds does have a nice ring to it).
I happened to have a machine-rolled length of flat bar lying around which would provide structure to my runners. However, making runners without this is easy enough: Stack up a few thin pieces of flat bar, bend them into the desired curve, and tack them together at intervals along their edges. I call it a "weld-lam".
I chose 2"x3/16" flat bar as a tread for the runners. Here I had my arch clamped to the table on spacers, elevating it to the center of the tread. I measured it with a nifty flatback measuring tape that my uncle gave me. I decided to leave the steel rusty – having some irregular touches here and there is always good. I prepped the piece by grinding clean some spots for welding to the tread.
Step 2: Clamp on the Tread
Vice grip C-clamps (or cowboy clamps as we call 'em) are great for metalwork. Using a zip disc to cut notches into the clamp's feet is a great trick. It allows the cowboy to grip thin edges, rod, corners, etc.
I clamped the tread to the arch and then used a hammer to tap it down flush with the table.
Step 3: Weld the Tread
Beefy tack welds are plenty strong to anchor the tread.
Step 4: Begin Scheming for the Legs
I decided that the front of the runner should have a 45 degree rake leading up to the front leg. I chose narrow, rectangular tubing that could stay well within the width of the runner tread for a sleek look, while offering lots of strength. I notched the tubing to sleeve over the runner's arch.
Step 5: Welding on the Front Leg
I clamped the runner onto the table and shimmed the leg up to the right height. Then I tacked the leg into place. Before running full-seam welds on the leg, I plumbed it by clamping the tread to the table and yanking the leg parallel to a square. I repeated this process after welding, to correct for any heat warping.
Step 6: Plan Out Some Geometry
I didn't have a complete vision in mind as I began to build this chair. Throughout this Instructable you will see me spend a lot of time staging parts and allowing form to develop organically. At this point I was starting to work out the seat angle and the angle of the runners and legs relative to the stump.
Step 7: Trapezoids
I chose to have each runner support a trapezoidal leg unit. Here I mitered the joints and tacked them together.
The runner felt disproportionately long in relation to the stump. I decide to shorten it by as much as my gut told me was safe. (We don't want people toppling over backwards). I finished tacking together the trapezoid, letting the rear piece of tubing meet up flush with the back of the tread.
Step 8: Repeat the Process
I used a sharpie to trace the pattern of my runner/leg unit onto the shop table and then went about making a copy for the other side of the chair. I decided that the chair should have some asymmetries, one of which is an armrest on only one side. Here you can see that I let the front length of tubing run long to support that armrest.
Step 9: Plan the Stump Mounting
After the runner/leg units were complete, I staged them with the stump to figure out how the existing components would come together.
Instead of sinking bolts into the stump, I decided to harness it with custom-made steel straps. This would give the stump a perceived isolation from the rest of the chair, making it appear distinct and replaceable. We associate such modularity with homogeneous, mass-produced parts. This association would create a nice tension and cognitive dissonance with the organic and inherently unique stump.
To digress for a moment... I believe that such philosophical considerations are as important as they are seemingly absurd. I employ them to create discourse with my work. This is born from boredom perhaps: I spend long periods of time alone with my projects, and giving them a voice makes for better company. That aside, I find that maintaining this philosophical conversation, almost as a rule, leads to a better aesthetic. It forces engagement with the work from new perspectives, conceptual and otherwise, and the aesthetic benefits from a hybrid vigor. Sometimes, when we are lucky, the dialog and philosophy themselves shine through, with a subtle clarity, into to the finished product, and the discourse resumes anew between between the object and the audience.
Or perhaps this hogwash is all in my head...?
Step 10: Stump Straps
I decided to use the same material for the straps that I did for the runner treads: 2"x3/16" flat bar. Here I was making the first strap, not yet knowing if there will be two or three in total. I began by taking a moment to appreciate the Asian Beetle (an invasive species often mistaken for a Ladybug) crawling across my work.
I added an extra inch and a half of length to each end of the strap that would be turned into a bolting bracket. I drilled 1/2" holes in these end segments. Then I scored (with a zip disc) and bent these sections, welding in triangles of the same material to anchor them. I now had a strap with a bolting bracket on both ends.
Step 11: Bending the Straps
Now I had to bend the strap into a ring large enough to fit around the stump, but tight enough to allow a bolt through the end brackets to cinch the strap tight. I employed the most basic, caveman strategy possible: bend the thing around another thing. I often use this tactic, but the strap was sturdy enough to make the process quite difficult.
Bending it first around an acetylene tank by hand, I ended up with some serious inconsistencies... I attempted to correct this with a ratchet strap to no avail. I fell back on fixing it with a compact bender. I felt bad about this, as not everyone has that tool, but figuring out a workaround with some clamps and a few random bits of metal would be pretty simple.
I finished the process with another old fuel tank. This one is completely empty, with the valve missing, so I was comfortable pounding on the strap with a hammer. This time the ratchet strap was helpful, pulling the strap tight enough for me to get an F-clamp on it.
Step 12: Clean!
The shop table is damned mess. It's covered in steel dust and welding spatter, which will keep project parts from lying flat. Time to sweep up a bit. Do this often!
Step 13: Joining the Runners
Now that I had a strap for the stump, I needed some cross-beams to weld it to. These cross-beams would connect the runner/leg units. I chose square tubing. Three lengths arranged in a triangle would offer good stability.
I set everything up on the table, being sure the runners lay flat and everything was nice and square. At this point, I tack welded the front two lengths of tubing to the legs. I waited to attach the third length, which would sandwich the stump into place.
You will notice that I left most joints tack welded until the end of the project. Tacks are plenty strong and much easier to cut off if necessary. This is an especially wise strategy when designing on the fly.
Step 14: Custom Bolt for the Custom Strap
It was time to get the first strap onto the stump. I needed a curved bolt to get the job done. I put half-inch all-thread into 3/4" conduit and bent them with a conduit bender. I did this to protect the thread, but in hindsight, bending the all-thread alone would probably have been just fine. In any case, after bending, I cut the all-thread and conduit down to length and then pounded out the all-thread.
Step 15: Attaching the First Strap
To determine the location of the first strap, I staged all the parts and made some sharpie marks on the stump. I used these marks to sink three temporary nails into the stump for the strap to rest on while I tightened it. I used a clamp to get the strap tight enough for the curved all-thread to slide in. I soon realized that welding one of the nuts in place would be helpful. One or two times I had to cut the all-thread shorter as it maxed out the reach of my socket wrench.
As I got the strap tighter, it became apparent how non-circular the stump was. Towards the end I was alternating between wailing on the strap with a hammer and cranking the bolt tighter. This aligned the strap's contour to that of the stump, allowing it to cinch down as tight as possible.
Step 16: Mounting the Stump
Here I staged the stump and welded the strap to the square tube cross-beams, adding the third tube behind the stump to trap it in place. At this point, removing the stump would take more than loosening the strap bolt, so the strap is essentially cosmetic. Which is fine by me, because it is good lookin'!
Step 17: Strap Number Two
I decided that the stump only wants one more strap. Creating the second strap went a lot smoother. I only used the large fuel tank this time and threw a turnbuckle in the mix.
Step 18: Backrest Testing
After attaching the second strap, I ratcheted on a temporary back rest, using various spacer blocks to adjust its angle and distance from the stump. My Lady helped me find the right fit.
Step 19: Backrest, Take One
I used a compressor tank and some 3/8" square rod to create a backrest outline. When I staged it in place, I decided it wasn't working.
Step 20: Backrest, Take Two
My take away from the failed backrest was that I would stick with 3/8" square rod. I decided to use it for curved, horizontal ribs.
I wandered around my (junk) yard until I found the perfect bending jig: An old water tank. I strapped the tank onto the shop table and clamped up various guides and such so that I could make consistent bends.
Step 21: Welding on the Ribs
I decided to support the backrest centrally, with a spine. I chose two lengths of the same rectangular tubing used for the legs. Using ribs as a clamping jig, I got the spine tubes at the right spacing and angle. I locked them into place by welding temporary plates on either end. Next, I measured out some tick marks to place the ribs with one-inch spacing.
I used a combo square to line up each rib before welding it in place. I wanted the backrest to be wider at the top, so I began at the bottom, using shorter ribs. As I neared the top, I decided to start tilting the ribs until the final one was curving straight up. I hoped this added detail would give the backrest better harmony with the sitter, the upward curve mirroring the arc of their shoulders.
Step 22: Align the Ribs
Of course, the ribs had slight variations in angle from all of my imprecise operations. No problem. I used my eyeballs and a piece of square tube to bend them into alignment.
Step 23: Time for Some More Pondering
Step 24: Tack on the Backrest
Once I found the right positioning for the backrest, I cut out some short pieces of tubing and connected it to the upper stump strap.
Step 25: Manicure the Ribs
I grabbed my trusty grinder to cut and groom the ribs. Working and thinking with deliberation, the chair and I coaxed a silhouette to reveal itself. Tape and a green hemisphere thingy were helpful in creating cut lines.
Step 26: Outline the Ribs
The ribs looked far too menacing and insect-like without a border.
Step 27: Armrest
I tested armrest heights with a piece of scrap metal and a clamp. At this point, I decided that all parts of the chair which will contact the sitter – armrest, footrest – should share the same theme as the backrest: 3/8" square rod at 1" spacing. (My favorite detail of the chair is two diagonal lines on the front corner opposite the armrest. These subtly suggest an alternate foot position. You will notice it in upcoming photos.)
After finishing the armrest, I decided it should receive a border like the backrest. My friend Skela suggested I leave the outer side open so that she could hang her bag on the rods. I thought that was a great idea and made it so. You'll notice the change in upcoming pictures.
Step 28: Footrest
I liked the idea of the footrest wrapping around the corner to the side opposite the armrest. Here, I was welding pieces of tubing to support the square rod, and then welding the rod into place. It was the middle off the night, and the documentarian in me dozed off. Whoops...
Step 29: Take a Shower and Get Some Sleep, You Look Like Hell
Step 30: Some Glamour Shots
The Rockin' Stump was mostly done! I was taking some pictures when over comes Barry Monigle himself (founder of ABCo Artspace) to pose for a few lifestyle shots.
I decide that the open end of the footrest needed to be closed off. All open tube ends needed a 45 degree rake and to be capped. Welds needed to be full-seamed and (as always) lots of grinding, but it was pretty darn close. And it was lookin' pretty darn good.
Step 31: It Ain't Called the Rockin' Stump for Nuthin'
Construction is complete! I haven't sealed the metal yet. I will live with the chair for a bit, taking time to decide if I will blacken the steel first.
If you actually read all my rants and rambles, I appreciate it!