Thursday, September 11, 2014

More mockups, and some tenoning strategies

Over the last few days I mocked up the top half of the chair I'm working on. This chair will have 7 narrow spindles, plus two somewhat beefier stiles on the ends. So the first step was to taper the bottom ends of the stiles to match my 5° reamer. Initially, I tried to do this freehand; the result was not bad but it took forever. So, I decided to make  a tapered tenon reamer. This was easy to do and worked well.
The first step was to bore and ream a hole in a piece of scrap. I reamed at slight angle, squaring the body of the reamer to the side of the scrap piece.

Then I planed the side until I opened up a slot of even width,

and then cleaned up the slot and bolted a plane frog on.

Peter Galbert, in this post, recommends using a Bedrock frog, which is kind of funny because Bedrock anything sells at a premium on the used market. I'm sure a plane Jane frog would be fine, but it just so happens that I have a bunch of spare Bedrock parts--some Ebay criminal sold me a dud years ago that I never got around to fixing up.

The tenoner worked great, although I fouled up the hole on my second try and had to redo it. The lesson I learned is that the tenoner works best--at least for me--as a finishing tool, after I had already shaped the tenon pretty close to its final size.

The other ends of the stiles have shouldered, untapered tenons. I found these much easier to cut freehand. With my stiles still in octagonal form, I marked off the tenon with a combination square and cut the shoulder all the way around with a backsaw.

Then I just used a chisel to split off the waste.

I split conservatively, and then pared to the lines. I concentrated on making as accurate a square section as I could first.

Then, I made an octagon, and finally shaved the corners off the octagon to get a pretty nice round tenon.

I didn't want to drill into one of my nice steam-bent oak crest rails without experimenting first, so I mocked up a rail out of cheapo spruce construction lumber. I just traced out the pattern twice on a 2 x 6, and laminated the pieces together. Here was my initial mockup, with no spindles, just the stiles.

I'm really glad I did this. I learned two big things. First, it was too high. At this height, the top of the crest rail would finish at about 37" high. It was really uncomfortable, but dropping it down to around 35.5" made a big difference. 
Second, the crest rail initially had the same backward-sloping angle as the stiles.  This caused the bottom of the crest rail to dig into my back. Angling it forward a little helped a lot. I redrilled the holes and postioned the spindles approximately where I'd like them to go:

The spindles obviously need to be thinned a lot. But this looks good enough that I'm ready to start working on the real thing, finally...

Friday, September 5, 2014

Prototyping and design

The chairs I am working on are not traditional Windsors--they're what you might call Modernist Windsors, with clean lines and most of the ornament stripped out. There are a number of chairs in this style that I like, such as Nakashima's New Chair, Moser's Eastward chair, and Curtis Buchanan's Patra's chair (as well as his and Peter Galbert's more traditional birdcage chairs). But there's no blueprint or scaled drawings to follow, so I'm making it up as I go along. This can get a little overwhelming, so I decided to do some prototyping. I got a couple cheap Southern yellow pine boards from the Home Depot and made a practice seat (my real seats will be made of elm).

The traditional tool for roughing out a seat is an adze. I don't have one, and they're not cheap. I do, however, have this:

It's a Lancelot "chainsaw" carving attachment for a 4.5" angle grinder. I bought it 7 or 8 years ago and never used it. I think it was only about 30 bucks. Boy, did it come in handy. I was able to rough out my first seat in about 15 minutes. Like a router, it tends to self-feed if you move it in the wrong direction, though not nearly as bad as a router does. But once you figure out the right direction, it's extremely controllable. Of course, it leaves a very rough surface.

But another half hour with the travisher and it was looking pretty good for a first try. And most important, I know what I need to do to make the first real seat a lot better than this.

The real seats will get scraped and probably sanded, but this was good enough for a prototype.

Next, I bored and reamed the seat holes. I'm using 14° for both the rake and splay. I got these numbers from a drawing of a birdcage chair in John Kassay's wonderful book, The Book of American Windsor Furniture, which has dozens of elaborate, scaled drawings. Using the tables in Drew Langsner's The Chairmaker's Workshop, I converted these angles to a 45° sighting angle and 20° resultant angle.

I forgot to take a picture of the reamer in use (the one I showed in this post), but suffice it to say that it works great. It cuts slowly, but that's an advantage, because it gives you multiple chances to dial in the right angles. My first hole was a little wonky--not surprising since I'd never done this before--but the other three were pretty much dead on.

This looks enough like the bottom half of a chair that I think I can tackle the real thing. But first, I'm going to try mocking up at least the outer spindles and the crest rail.

Friday, August 22, 2014

Travisher is finished

After a couple detours, I'm done making a travisher. The lack of one was the last major impediment to moving on with my chair project, so I'm excited to start carving the seats.

There is not much info on the web about making travishers, so some pics and explanation may be helpful for folks who want to try rolling their own. There were two sources that were invaluable to me, however. The first was Peter Galbert's blog, of course. There is a ton of great information and many pictures of Pete's travishers, and I based mine pretty closely on his design.
The other source is Claire Minihan, who actually makes the travishers that Pete sells. She answered some emailed questions for me, and even better, sent me some photos of the construction process. Than you, Claire! Claire's and Pete's blogs are linked in the blog roll--check 'em out.

OK, so the first step was forging the blade. I had some odd-shaped scrap pieces of O-1 tool steel, so I hacksawed to shape and drilled a couple holes. Then, I heated the blade to red in my forge and hammered it around a 7" diameter piece of pipe that I scrounged from a local construction site. Then I "normalized" it (heating it past the magnetic point, about 1500° F, and then cooling it slowly), heat treated it, and tempered it. Here is the finished blade:

Above, you can see there is some pitting in the center of the blade, which is mostly due to my inexperience at forging. This is just cosmetic though; the edges cleaned up very nicely.

This photo shows the blade after grinding; I did not grind it until after it had been hardened. Look at Ms. Minihan's blog for an excellent description of how to do the grinding. She bevels the blades at 27°. I went a couple degrees higher than that, I think, but it's pretty close.

With the blade finished, I started on the body, using some nice quartersawn beech I recently acquired. There was was lots of drawing to come up with a shape I liked, then I made a cardboard template.

After that, I bandsawed the blank to shape, followed by lots of tedious planing, chiseling, rasping, and scraping. I spent a great deal of time making sure the bottom conformed closely to the curve of the blade, and I think this was time well-spent.

Then I forgot to take photos for a while. Oh well. In the pic above, two 8-32 threaded inserts have been installed to hold the blade, and the escapement (where the shavings go) has been marked out. After cutting along all the vertical lines with a backsaw, I broke out the waste with a chisel, then chiseled a smooth surface, finishing up with a mill-tooth file at the end. This was really easy--beech works like butter. I can see why it was the traditional wood for handplanes; it is dense and hard, but very easy to work with hand tools, and not prone to tearing or chipping.

Galbert travishers have a brass sole. I didn't have any brass on hand, so I decided to make a glued-on sole out of cocobolo. This presented some interesting challenges. For one, I needed a perfect fit between the cocobolo and beech to get a good glue joint. To do this, I started with an oversized piece of cocobolo. After getting the curve as close as I could by eye, I shot some spray adhesive onto 100-grit sandpaper, glued it to the bottom of the beech blank, and carefully molded the cocobolo until I had a perfect fit. Afterwards, the sandpaper just pulls off, and the adhesive is easily cleaned off with mineral spirits.

Then I glued it up:

Above, you can see the virtue of saving your leftover bandsaw cutoffs! There is also a stack of cardboard shims to help take pressure off the ends of the travisher.

Then I cleaned everything up and marked out the blank for sawing. This pic also gives a good view of the escapement. Sorry about the Chuck Taylors  :)

After bandsawing, there was more planing, rasping, and scraping until I got an even reveal on the sole. It needs to be about 1/64" below the cutting edge, and the inside needs to be beveled at around 45° to form a smooth transition to the escapement.

 The most important information I got from Ms. Minihan was regarding the shaping of the sole. She specified a 6° bevel, with a 1/32" flat directly in front of the blade. I got pretty close:

The only worrisome thing is that the cocobolo gets very thin at the bottom of the bevel. But it seems fine for now, and can always be replaced.

Finally, I cut the rather exuberant chamfers on all the long edges with a chisel, then scraped and sanded them. And that's it! Here are a couple more finished shots:

Oh yeah, it works:

The pic above shows that the tool cuts really well, but I badly need experience using it. So far, I'm able to hog off thick shavings, which is great, but I haven't yet acquired the touch for a fine finish. But with 4 chair seats to shape, I will get plenty of practice.

Monday, August 4, 2014

Making a Tapered Chair Reamer

One of the time-consuming things about making chairs for the first time is the never-ending list of specialty tools one needs. And if I don't want to go broke, I need to make, rather than buy, most of these. So, I am making incremental progress on that front. This week, I finished up a tapered reamer, used for boring the tapered sockets for the legs.

To the best of my knowledge, the design of this reamer was invented, or at least popularized, by Jenny Alexander; there's also a good article by Peter Galbert. One starts by making a blade from an old compass saw blade. These are harder to find than 'd imagined, but I eventually found a whole box of nice ones on Ebay for really cheap. I cut the blade down to 10", ground off the teeth on the 6" bench grinder, filed the edges straight, and then ground a 70° bevel on both edges. Below shows one of the saw blades next to my finished reamer blade.

The finished blade tapers from 1 3/16" to 5/16", over 10" (more on that later).

After that, I turned the shaft of the reamer on the lathe, drilled a hole for the handle, and cut a slot for the blade. The finished tool:

I tested the reamer out on some pine. It works as advertised!

OK, so here's a slight conundrum. Nearly every chairmaker who builds these call them "6° reamers." But if you do the math on the dimensions they use, the angles are actually in the 4°-5° range. I decided to be practical about this and use the dimensions that experienced chairmakers use, rather than worry about the angles. So, this one is a 5° reamer. I think it will work very nicely.

Next up: a travisher.

Wednesday, July 9, 2014

Double Iron Coffin Smoother in Goncalo Alves

I just finished up a new coffin smoother made from goncalo alves, a South & Central American wood prized by many planemakers, including Phil Edwards (Philly Planes). The plane uses a vintage, probably late 19th century, Buck Bros. double iron. Below is a sort of diary in pictures from making the plane. Hope you enjoy it!

Cutting the mortise.

Cutting the slots for the abutments.

Fitting the abutments.

Making the wedge (it starts out very long, so there's something to hold on to).

Testing the plane while the body is still square.

The body cut and planed to the coffin shape.

Marking out the arcs for shaping the back.

The finished plane after two coats of oil.

Final testing on a piece of Ipe, one of the nastiest woods to plane that I know of.

The finished surface.

Thanks for looking.

Wednesday, June 4, 2014

Chairs: Bending the crest rails

My chair project has been languishing, but I'm getting back to it this summer. This week, I started bending the crest rails. The first thing was to make some improvements to the steam box I built last summer. Originally, steam was supplied by a single tea kettle, powered by a camping stove. This was under-powered and a little unsafe, so I upgraded to two electric kettles, one from a yard sale, the other from ebay, total cost about $30.

Here's a closeup of the steam source. Another key to improving performance was to shorten the plumbing as much as possible. That's the reason for the cinder block--to get the kettles closer to the bottom of the box.

With two heat sources, the box works much better. Thanks to Peter Galbert's blog for the idea!

The crest rails were split last summer from the white oak log I bought, and have been drying slowly in my damp basement. They look pretty ratty:

But they clean up nicely with a bit of drawknifing and handplaning. This one has a beautiful large ray on the right side.

After steaming the rail for about an hour, I clamp it to a plywood form and let it set for several days. It looks all dark and stained with black splotches after steaming, but that will come out with a bit of cleanup.


It's been rainy here, which has hampered the steaming somewhat. Once I get the rest of the rails bent, I can move on to the seats.

Tuesday, June 3, 2014

A woodworker's charcoal forge

While normal people were barbecuing hot dogs and hamburgers on Memorial day, I was barbecuing something different…

Plane irons!
As you can see, I finished assembling my charcoal forge.

The construction is pretty simple. The firepot is a truck brake drum.  A floor flange is bolted to the bottom of the drum. Not shown is a tee fitting; there's a 4" nipple below the tee, with a cap over it, to collect ash. Then there's a 12" nipple, which ends in the fancy looking thing with the red handle. That's a gate valve, which was twenty-something dollars, but worth every penny. The valve connects to a piece of PVC, which pulls airflow from the fan.

The fan is a wood stove fan that I got from Surplus Center for about $40, shipping included. The frame for the fan is just plywood and construction lumber, nothing fancy.

The forge works really well. I haven't yet been able to get it up to welding heat, which is around 2000°, but forging/hardening/annealing heat, typically 1400°-1500°, was no problem. But I need practice. My first effort was moderately successful. I tried to harden a plane iron and a chisel. The chisel turned out well, but the plane iron, not so much. This is to be expected; as Ron Hock pointed out to me, if it were easy, everyone would do it.

Tuesday, May 13, 2014

Edge Failure

Ugh. This is not a fun post to write. I did say, at the beginning of my skew mitre project, that I might fail…and I have, at least temporarily. Or, to be more precise, steel failed me.
So: I intended to use a vintage W. Butcher iron, that I'm pretty sure was never used. It took a lot of work to grind it to the proper shape and coarsely flatten the back:

You can see that the back is slightly concave, so there is a silver-dollar-size area above the cutting edge that is not flattened. But that's OK. There is a good 3/4" of flat steel above the cutting edge, probably enough to last a lifetime, and the sides where the wedge prongs make contact are also flat.

Next, I polished the back with successively finer grits of sandpaper, then moved to my oil stones, working the back until it was smooth enough to take a selfie in the reflection:

Then I made the wedge. At this point, the plane is not finished--the wedge is not shaped, and the plane body hasn't been shaped and chamfered--but the wedge fits great.

Now I was ready for some test cuts, and this is where everything went south. After just a couple passes on end grain, I started to get ugly scratches. What happened was that the cutting edge was folding over, microfracturing. I increased the bevel angle to about 27°, which is as high as I can go in this low angle (38°) plane before I start to have clearance angle problems. This helped a little, but the problem remained. The blade is simply too soft.

So, for now I am stymied on this plane, but all is not lost. I'm determined to make some lemonade from these lemons. Last summer, I started building a small brake drum forge for basic blacksmithing operations…like hardening steel. I never quite finished, but this blade failure was just the kick in ass I needed to get back to the forge. I've got it done, and in a week or so I'll give it a test run. If all goes as planned, I'll see if I can re-harden this iron. And if that doesn't work, I'll try making a new iron from scratch. Stay tuned!