Monday, July 27, 2015

Walking stick complete

So here's a few photos of the completed walking stick. I'm happy with how it turned out. And it justified purchasing a drawknife, so that's a win-win!

Progress on Four-legged Three-legged Stool

After much more time and energy than I care to admit, I'm making good progress on the two cherry stools. These are my four-legged version of the Tage Frid three-legged stool design. I'm working on milling wood for all the parts (which is challenging because the humidity is making them move all over the place), but the biggest achievement so far is the progress I've made with the seat connector piece. This little 4" by 5" chunk does the work of keeping the whole stool together. (By the way, when does a stool become a chair? This is going to have four legs, so maybe it deserves chair status.)

This piece joins the front part of the seat to the seat back but also connects to the back legs. That's more action per square inch than any other part of the chair. So here's the rundown on what I've done to the connector so far:

Made a blank out of plywood (3/16" thick pieces of cherry laminated in perpendicular layers)
Straightened it up and cut it down to size
Cut a 4" wide tenon to fit the mortise in the front of the seat
Cut a 75 degree angle on the back

Next up:
Cutting angled dovetails to join the seat back
Cutting an angle on the underside to join the seat
Cutting 13 degree bevels on both sides
Cutting slots to fit dovetails on the two back legs

This is a lot of stuff, especially since two of the upcoming tasks require making jigs that work just fine in my head but haven't been attempted in the real world. And after all this, I have to make the rest of the stools (I mean chairs).

Friday, July 10, 2015

Walking Stick

A client approached me recently about making a walking stick from a piece of wood she and her husband picked up on a hike. I thought, how difficult could it be to take a large piece of wood and make it into a smaller piece of wood?

When I saw the wood at first, I didn’t recognize the species. I thought it could be anything from ash to oak to cherry to walnut. I got out my new hatchet and started removing the bark. When I got down to the heartwood, I realized the species was hickory. It felt like I was trying to cut marble.

I fretted about how I was going to remove enough wood to make this stick functional and attractive, considering using a chainsaw or a grinder. But I realized it was kind of fun hacking away at it with the hatchet, so I kept going. I’m new to using a hatchet, so this was the perfect way for me to learn about its capabilities and how to use it. I found that the hatchet was great for doing a kind of hewing. I would chop perpendicular to the grain in a long row, then go back through with glancing chops to remove the wood. It worked really well and removed material much faster than I imagined.

After taking the piece down to a thickness of 2” or so, I used a drawknife to refine the shape a bit more. I don’t have a shaving horse, so it was a challenge to secure the wood. I managed to lean it against the house or hold it down with my foot at an angle against a chair. It wasn’t pretty, but I made progress.

With the wood down to the approximate thickness I was going for and basically round, I used a spokeshave to do more refining. I love using a spokeshave. It’s an incredibly versatile tool that I am incorporating more and more into my work.

The stick is quite rustic on purpose. There are some knots here and there, some worm channels and even holes that go straight through. I chopped off the bottom and the top, drilled a hole for a strap and sanded it. The hickory is amazingly strong. This stick will outlast anyone who owns it. Once I apply a few coats of finish -- I’m using boiled linseed oil, polyurethane and some mineral spirits. I’ll post a photo once the finish is on, but for now, here it is.


Monday, June 8, 2015

Engineering solution?

To get around the issue of the grain running in the wrong direction on the connector of my modified Tage Frid-style stool, my idea is to make the connector piece essentially out of hardwood plywood. I created the plywood with ¼” thick plies of cherry in an alternating perpendicular orientation. This way, potentially, the wood on the sides of the connector piece will have a substantial amount of end grain to connect to.

I made the plywood, cleaned it up a bit on the jointer and planer, and cut the sides with a 15 degree bevel. This bevel establishes the splay angle of the legs. To complicate matters, the leg will also be joined at another angle that will establish the rake, making this a compound angle dovetail. (The splay angle is side to side; the rake is front to back). I used the test leg I cut for my first test since it already had the tenon that will form the vertical tail of the dovetail. The trick to cutting angled dovetails is to not think about the fact that they are angled dovetails. Just mark everything clearly and cut to the lines.

I was a little nervous when I tapped the dovetail together because this is where it broke in my last test. The fit was a bit too tight and I had to do more pounding than tapping to put it together. The joint survived the pounding without a budge. Now that it was together, I had to try to break the wood. I wrenched it around, simulating the wracking force chair legs have to endure. Nothing moved; no cracks anywhere. I put the leg securely in my vise and got out my hammer. I bashed it in all directions and still it didn’t move. Finally, I climbed up on the bench and put all my body weight on the joint. There was a bit of creaking, but I think that was me and not the wood.

I’m satisfied now that this plywood method will hold. Not only does it provide end grain for the dovetail but each layer bolsters the other layers against movement. I’m considering adding another ply of cherry going side to side on the underside just between the two leg joints and adding a small stretcher a few inches down from the seat, which will serve two purposes -- fortifying the two legs and serving as a handle to move the stool. Also, I feel like the tenon can be a touch wider, so i’ll incorporate that as well. All in all, I’m happy enough to go forward.

Wednesday, June 3, 2015

Engineering Problem

I love a good engineering problem. I think my favorite thing about woodworking is that it’s the intersection of engineering and creativity. I’m working on a design for some barstools based on the Tage Frid three-legged stool. The problem is that the seat height needs to be about 28” and I’m afraid sitting on a three-legged stool that high would make it top heavy. The last thing I’d ever want is someone falling off of one of these stools. Frid swore by the design of the third leg in the back. I’ve made a couple of those stools now, and I agree that it’s fine when you are sitting at a low height. People aren’t used to having one leg in the back, so when they shift around expecting the seat to be solid, they could topple over.

The second problem is that I’ve seen examples of people making the Tage Frid stool with slight variations and they never look right. The proportions are critical to this design. They make the design. So how do I add another leg in the back without messing with the proportions? I did drawings where I widened the connector between the seat and back to accommodate two legs joined with through tenons. They looked awful. I found that no matter how great the rest of the stool looked, my eye always went right to the connector, which called attention to itself because it was so out of proportion to the rest of the stool. My proposed solution is to join the legs on the sides of the connectors with vertical dovetails.

So. The other problem is the grain direction of the connector. The grain needs to run straight from the dovetails on the back to the tenon on the front. If you make a hole on the side, you leave a section of short grain which is vulnerable to breaking. Indeed, on my first test run, the back chunk of the connector broke immediately. This is a critical area of the stool, so that part of the connector needs to be strong.

My idea for mounting the legs in that spot with a dovetail is to make the connector out of laminated perpendicular plies. It would be like plywood, except this would be hardwood plywood. This is a compromise, as most design decisions are. My hope is that the plies will adhere well and strengthen each other. Time to do some tests.

Friday, November 21, 2014

Tage Frid Three-legged Stool

I just finished a series of posts on the Craftsy woodworking blog about building a Tage Frid inspired three-legged stool. It was a challenging build from start to finish. These posts detail the whole process. My version is made of Ambrosia maple.

Craftsy posts:

Wednesday, September 10, 2014

Robotic Furniture

This article introduces the Roombot, a robot that assembles itself into different pieces of furniture -- Transformers-style. The inventors describe it as the "future of furniture." Why am I not worried?