Its easy to get sidetracked making snowshoes

Finally fed up with less than awesome results cleaning up inside radiuses (such as the staves for snow shoes), I cut a dai block. It was a piece of firewood, and now something to get chuffed about because it produces workmanship of certainty. It may yet end up being a piece of firewood, some oak just doesn’t handle repeated wedging of the plane iron and it really loosened up. Cutting a block like this only takes a couple hours, you can use a blade that you already have, voila, any radius you need is possible and there is no need to suffer the use of a portable belt sander, perish the thought!

The steam bending routine is well organized, all it really takes is proper grain in the lumber and practice. Oh, and pre-soaking my staves overnight helped too.

I added a thermal efficiency enhancer to my boiling pot. I’m thinking I’ll sell the idea to SpaceX for their next rocket. Damn its cold and windy recently.

Perfect weather for staying warm, Lilly has the right idea – thermal efficiency! I’m training her to sleep rough, teotwawki is coming! Seriously we have a fireplace, the kid just likes boxes.

Steam bending has a real charm, the smooth continuity of grain, giving something mutability and strength in tension from curved shape. It makes me want to write a poem but I think it would sound like Buckminster Fuller trying to tell a dirty joke.

That pondering of grain never really goes away, your appreciation of it just deepens over time.

Some little shuttles for the lacing. That’s butchers twine on the small one, not nylon. I just had to see how it felt in my hand with a bit of cord, you know?

For all my romanticizing not every part will be steam bent. I’m using a style of foot binding that needed a thickness and radius of curvature not suited to bending with heat.

I have to consider that you could be really SOL if your shoe brakes and you’re out in the bush in deep snow, at its essence snowshoes are a survival tool, quality of construction can never be sacrificed.

You need some way to bind the tail of the snowshoe frames together, bolts, rivets, wire wrapping. Somewhere in my readings I recall that snowshoes were often made by boat builders as winter work. Its a natural fit then to use copper rivets and nails over roves.

My boat building knowledge is all over the place these days: Douglas Brooks, PBS Nova: Building Pharos boat… and the new America’s Cup cats that are closer to airplanes dipping their toes in the water, wild stuff.

I really admire when I see a smith that can move material fast, draw it out, Brian Brazeal comes to mind. When you first start learning this stuff you pound enthusiastically but to seemingly little effect. The copper grounding wire I used to make these rivets turned out to be good practice (albeit tiny), no forge fuel required.

I’ve used flush countersunk rivets in brass for yarn spinning tools, mild steel works fine as a rivet header.

The hacksaw in the background is distracting…use a cold chisel to part your rivets and the head has a good shape ready for peening down.

The grounding wire is annealed so making the rivet work hardens it a bit, a good thing in this case. And these rivets have that hand forged look that brings a smile to a weary eye.

The round rivets are for attaching the leather straps of the binding to the bent lamination seen earlier. The square ones for riveting the frame. My roves only cost one penny each, all minted before 1981 when the US mint stopped using copper.

I don’t have a square nail header, love to forge one but its interminably cold and windy of late. Thus, it was a neat trick heading them in the metal jaws of a small bench vice. And I ended up forging three times the number I needed to get four that match well enough.

That’s all for today, my back is really sore from being bent over while lacing the snowshoes. Its slow work for me but looking great, the subject of another days post.

A Look at Hitachi Beam Mortisers

My shop has two new additions, a hitachi  chain mortiser and hollow chisel beam mortiser.  These tools are for cutting timber framing mortises in beam sections typical of Japanese wooden architecture. When I first got hard into carpentry they seemed like rare unicorns, not available in the American market. Last time I looked, there’s sellers on ebay offering every major brand now, Hitachi, Makita, Ryobi. And these tools are even more common on Yahoo Japan auctions, just with better prices and more selection.  I had intended to only get the hollow chisel mortiser, but at only 6,000 yen the chain mortiser was too good a deal to pass up on, plus I like the color, haha.  Take two zeros off to get the rough yen to dollar conversion.

The only shipping option other than Sea Mail was EMS, both of which I assume use USPS to get the box to your door, so this was a major test of shipping and handling reliability. I paid extra for protective packaging, which apparently meant entombing the parcels in heavy bubble wrap. I would have appreciated double boxing at a minimum short of crating, but through some miracle they arrived nearly undamaged, mainly due to the robust quality of the castings and parts on these machines.

Hitachi’s CB21 chain mortiser, as it arrived. It’s used, so of course a bit of rust and a broken plastic adjustment knob from shipping damage. The chain mortisers seem to sell for quite a bit less than the hollow chisel mortisers in general. I could be wrong about this, but it looked like this model is out of production, and I couldn’t find replacement chains from any Japanese merchants which could be part of the low price I paid. I’m holding out hope though that I can find a chain from a different manufacturer that will fit.  

I got her all cleaned up and lubricated, ready to test. The chain was still nice and sharp. Both of these machines are meant to run at 100v, and I read through lots and lots of debate about whether or not its advisable to run them at 120 volts without a voltage converter. In general it doesn’t seem to be a problem, but maybe will shorten the motor life a bit.  One of the major limitations of this machine is the maximum width of beam it can ride. At full open between the clamps you get about 7.5″, rather inconvenient if you think you’re going to be mortising a bunch of 8×8’s.  The chain is 18mm wide, so can cut your typical 30mm wide mortise with a single throw of the axis control. I love though how robust the guide rods and casting are on this thing compared to the Makita 7104. Once I got it cleaned up and lubed its really smooth and rigid.

This is a shot of the lever arm that controls side to side movement of the chain. It has presets for different widths of mortises.

Here’s the other side of that control lever. For some reason as the numbers here get bigger the mortises get narrower, so it has me a bit puzzled. Where I have it set now it will cut a 28mm wide mortise, just wide enough to leave 1mm of wood to clean off the side walls. In total, it may not be a new Mafell, but I really can’t complain seeing as both of these machines plus shipping was 1/3 the cost.

The hollow chisel mortiser arrived this morning, and had me really worried to judge by the look of the packaging. Despite the mangled look of this the bubble wrap underneath did its job except for a bent guide rod on one of the clamping fixtures.

This is Hitachi’s 30mm BS30SA. The ‘SA’ part of the model number means it can handle a 155mm long chisel. The BS30’s are more common and less spendy.  I’ve had the good fortune to try this model before, which is why I looked for it specifically, Makita seems to make good hollow chisel mortisers too, and they go for a bit less at auction.

I pulled this machine apart a bit to clean the old gummed up grease from the ways and guide rods and re-lubricate.

Now, 30mm is a big chisel to push through most any wood, so I tested on some red cedar after sharpening the chisel and auger. Western red cedar is cruel to less than a finely honed edge and it crushed on the end grain, anybody know a source for conical diamond hones big enough for a 30mm chisel? I bought this machine with square pegging in mind so next thing I need to find is some smaller chisels, but at least they can be found for sale without trouble. One thing I did try that worked quite nicely was using the chain mortiser to rough a mortise and then paring the side walls with the hollow chisel mortiser with the auger removed, keeping things really dimensionally tight and consistent.

These are the first power mortisers in my shop, I still prefer to make smaller mortises by hand and frankly I’ve put in the time  to get good at it, so tradition holds some sway with me. Up to now I’ve drilled larger mortises and then chiseled, which is by no means slow (ok, I’m still slow), but it helps to have the extra efficiencies when working by yourself trying to get your timber cut and assembled before too much dimensional change from seasoning.

What do you think, are these things worth it? I have a couple projects in mind and a good sawmill down the road that cuts local timber, a match made in heaven.

 

Twin Mortise Chisel: Nihon-Mukomachi-Nomi

Ever since reading the description of a twin mortising chisel in Odate’s book “Japanese Woodworking Tools” I’ve hoped to some day acquire one.   Its a truism that you can’t always get what you want, and because generally there is more than one way to make mortises a chisel like this definitely isn’t the first thing to go after if you’re trying to build a tool set. But it sure is nice.

I found this one through Yahoo Japan auctions, using Buyee to handle getting it out of the country. Usually I see these chisels half used up and part of a set of other chisels, but at the time I was looking this one popped up, a new chisel from old stock that had sat somewhere for a long time and offered as a single item.

The chisel widths are 6mm, with about a 4mm gap in between.

Up to now I’ve ben cutting twin mortises, but with a single 6mm chisel. Here they are side by side for comparison. The twin mortise chisel is a bit thicker, but it may be just the slightly larger size of chisel you can find between a cabinetmaker’s bench chisels and the larger timber chisels.

So I set about eagerly sharpening, hungry for that first try of a new tool.

For a first rough stone to take the steel to I’ve been using a Beston 400 grit, a nice affordable option. Its been wearing down quickly though, so I’ve lined up a Shapton Pro 320 grit stone to replace it when the time comes.

My 6000 grit Shapton on gass polishing stone is down to a thin little whisp of stone left. They are harder wearing stones but they won’t last forever. A synthetic Kitayama polishing stone is waiting behind it. I’m quite interested to see how it compares, I usually don’t bother with polishing the edge beyond 6000 grit except for sharpening my straight razor or seeing how fine a shaving I can pull with my kanna.

I did run into a disappointing observation with this chisel. The fork of this chisel was spread slightly apart, about 25 thou from the bottom of the slot to the cutting edge.

I gave this a lot of thought, tried cutting a few mortises, and decided the tolerances actually needed addressing for this tool to work properly. I don’t know if this is just something that happened in quenching or poor quality control, but without a fix the chisel would be hard to control and cut tapered mortise walls on the inside. It was disappointing to say the least.

But I didn’t start whacking it with a hammer right away. I have a habit of getting new tools and thinking something is wrong and then correcting it in error. For instance, have you gotten a kanna blade that wasn’t sharpened square to the sides in a new block? I’ve erroneously “fixed” that only to find that it was sharpened that way to match the block. Same thing with a double bladed marking knife…cutting edges that came from the factory at different lengths. Figuring that had to be wrong I “fixed” it and only then realized that it was supposed to be like that for a good reason. The blade has to tilt over a bit when marking so that the back bevel rides plumb against the straight edge, thus the different length of blade so the two cutting edges contact the wood evenly.

So definitely sleep on it before deciding to fix something you think is wrong, give it some real consideration and see how it works in the cut before making twice as much work putting the tool back to right.

Here’s another example, a two inch timber framing chisel I picked up at a small mountain antique store for $20 bucks. For comparison I’ve placed a 30mm timber chisel next to it, makes it look tiny, haha, but its not. I thought it was the most amazing deal until I got it home and noticed that the bottom of the chisel was way convex. Honestly I beat the hell out of this thing with a 3lb sledge hammer trying every technique I possess to get some of the bend out.

The marks on the side weren’t from my straightening attempts, some body had stuck this chisel in a knurled vise jaw and cranked down really hard. Can’t imagine why. It has a thick cutting steel forge laminated in there, wouldn’t budge no matter how I nudged the mild steel around it, and didn’t break even with me hammering the cutting steel directly, which I can’t recommend. Sometimes you need to just set the hammer down and leave it be, the chisel still works, just held at a different angle when chopping down.

So now duly considered of the dangers of ignorant hizumi I stuck my new chisel in a vise and tightened it where I needed to get a bit of deformation to bring the blades back in line. I did this slowly, by degrees of measurement with my dial guage, and thank god it worked. I had to bend the forks in 75 thousandths past where I wanted it to end up, which doesn’t sound like much when you’re measuring by the thou, but it was clear and visible just how much I was straining the chisel to the naked eye. The tool steel lamination on this chisel extends past the slot all the way to the heel of the chisel. I’d really love to see how one of these is forged, because they still manage to get the lamination to wrap the sides of each blade.

A chisel like this needs its own marking guage, one of my favorite little birdie things to make. Its real important to get a good fit of the beam to the guage block, make sure it comes through nice and square, just snug enough not to move when the keyed wedge is loose.

Nice and comfortable in the hand, easy to adjust, and it doesn’t hurt if it looks nice too.

I use tempered finish nails for the pins, sharpened to a chisel point with a file. The thickness of the nails gives you some adjustment room for getting it to exactly fit the chisel.

Now I really need to make some shoji, this thing is begging to be put to use. The appeal of this tool…double the mortises in the same time. Twice the glue area compared to a single mortise, or I imagine you can cut shorter tenons and shallower mortises and have the same joint strength compared to a single mortise. I love it and its  a classic tategu-shi tool.

Don’t despair if this isn’t a tool you can lay your hands on. How about making your own by slotting a stock bench chisel? I know I’ve seen chisels modified like that. You wouldn’t have to grind the slot to the full length of the chisel, just to the depth that you expect to be cutting mortises, probably no more than 1.5″. It would be a good little challenge to make accurate tool surfaces in hardened steel. When I was first starting out I definitely didn’t have money for all the specialty chisels and made my own 1/4″ dovetail chisel and fishtail chisel, even a little 1/8″ mortise chisel. They’re cheapo Harbor Freight steel, but I still use them and carry them in my chisel roll. They’re the mutts of my collection but give good service, so I take pride in using them and my work is the better for it.

Steambending Snowshoe Frames

Thinking about what defines ‘shokunin spirit’ it can give pause. I’ve recently been enjoying the work of printmaker/carver David Bull, who tells the story of meeting wood block carver Ito Susumu:

I’m thinking of the exchange where David asks Ito how he feels about having to carve the same image so many times in his career. Ito tells David that he’s just a hobbyist, because he carves what he wants. I guess my point is that when opportunity knocks, go ahead and do the work that is asked of you.

Which brings me to snow shoes… I’ve been commissioned for a couple pairs. Of course, the only answer when asked if such or such a thing can be done is, “Hell yah, do that all the time, haha.” I’m looking forward to getting back to a more daiku-centric work, joinery and the like, but its winter and snowshoes/snowshoe furniture will sell well up here in the mountains.

Supposedly in the mail on its way to me from Japan are a hitachi chain mortiser and hollow chisel beam mortiser bought at auction from Yahoo Japan. I’m excited, super excited. The chain mortiser, 6000 yen, really? But it costs about $300 dollars to get something that heavy shipped over, lol.

So I  started with a book, “Building Wooden Snowshoes & Snowshoe Furniture” by Gil Gilpatrick.

There’s a lot of different skills that go into making a pair of snowshoes: steambending, weaving the webbing, and the leather bindings that hold the shoe to your foot. I was doubtful of finding straight grain white ash that would bend successfully, so that’s the first challenge I’ve taken on, everything else will follow more or less easily.

Developing the pattern from the book was the first step, fairing the curves with a bent piece of kumiko. Damn useful stuff that kumiko.

The pattern represents the inside edge of the snowshoe frame, and is used to lay out the bending form.

Snowshoes come in pairs, so the formwork is double sided.  The bend is one of double curvature at the toe, sweet and smooth.

I decided to go the wood route for a steam box. My setup is just simple things that I had lying around, with a large tea pot for my boiler and a rubber tube to transmit the steam to the middle of the steam box where the bend in the frames is tightest. In addition there are dowels along the length of the box that hold the staves off from the bottom so that the steam can get to all sides of the piece. I should have pre-soaked the frame pieces overnight, the first piece came out at two hours feeling stiff and like the steam wasn’t evenly distributing in the box. I cracked open both of the ends of the box so that a little steam escaped from both ends, it seemed to help.

The frames are nine foot long and shaped for the bend from their own pattern, then cut on the bandsaw and smoothed. One of these days I’m going to make a convex spokeshave for smoothing inside radiuses, but until then my hand scraping card works adequately.

Steam bending takes practice…I had an assistant to help as well.  But we were too slow the first time and made numerous small errors. The first stave cooled too much and failed in numerous places. After a few adjustments we tried again. Success! Or close enough, haha. Thankfully I saved the best Ash for the next time.

Where the upturn of the toe was unsupported by metal strapping I got a little split on one side, but its shallow enough that it will be sanded off I think. In steam bending the softened wood compresses easily, but still can fail in tension. The bend for the tip of the toe has support to keep the bending in compression, that was the easy part. Getting it around the rest of the form, especially at the tail, was harder.

I can see a couple of places where more wedges are needed to push the wood to the form. All together, I expected failures the first time around, but it was really exciting to see the wood take shape! I don’t want  to be the idiot hopping around on one snow shoe, so I guess I’ll have to try again and again until I get the hang of things.

The sides of my steam box cupped a bit, haha. But the joinery held together and swelled steam tight. I’ll try again next week when I can get an extra set of hands. In the mean time its on to sourcing the nylon for the webbing and other assorted parts and pieces, stay tuned.

 

Hopper Joinery

The hopper is an old form you can still see all the time in things like wheel barrows and baby’s cribs, sloped sides meeting in compound miters. Although initially intimidating, learning to determine the cut angles for butt or mitre joints is as simple as drawing a few lines with a carpenters square, opening up a whole exciting world of non-orthogonal intersecting surfaces.  Learning hopper joinery is step number one towards Japanese roof carpentry, heady stuff indeed!

Although there are western methods for deriving these cut angles, I learned it first from Chris Hall’s second volume of carpentry drawing books. They’re only available as an e-book and not cheap, but its still cheaper and faster than learning Japanese. He kind of bludgeons you (in a good way) with numerous methods of understanding this stuff, from a basic trigonometric understanding to developed drawing to my favorite and the dead simple approach with the sashigane.

Since I want to keep this simple and don’t want to rip off Hall’s hard work in teaching this stuff I’ll omit the Japanese names for the various parts of the unit triangle.  Also of import is that this method only works for regular slope, regular plan. Which is to say, the splay is the same on all four sides and they meet at ninety degrees in plan view.

Slope is expressed most commonly as a ratio, here 4/10. I apologize for the crappy surface of my work beam, the rest of it was scraped clean, but I didn’t want to erase the unit triangle until work was complete. Hopefully its clear though that I used the square to draw a triangle with right angle sides of four and ten, with the edge of the beam forming the hypotenuse. The short segment of the triangle gives the bottom bevel angle of your hopper. From there a line is extended up square to the hypotenuse and meeting at the right angle . The length of this segment that divides the unit triangle gives the face cut angle, 3.75/10. Further, the hypotenuse is now divided by this line into two segments, a short and a long. The long segment gives the edge mitre angle 9.375/10 if you want a hopper to join with 45 degree corners in plan view, and the short segment gives the butt mitre angle of 1.5/10.

I’m using butt joints, so just as I drew the original 4/10 triangle, the square is used to lay out a line on my beam for the edge butt angle and the face cut angle, and then transferred to a bevel gauge.

Its handy to have a couple of bevel gauges, each one set to the needed angles.

Apparently Shinwa makes a western framing square in stainless steel, couldn’t resist! It has the normal rafter tables and brace length table, but no Essex board foot scale. I don’t think I’ll miss that one though, never having used it.

Rather counter-intuitively, for a hopper with butted edges, the inside length is longer than the outside, which you have to watch out for when marking the edge angle.

Once you know which side of the board faces inward on the hopper you can mark the bottom bevel.

These hoppers are a real pain in the ass to nail together without some kind of joinery, so I decided to cut a simple dado. For marking the width of that dado you need to use the length of the cut line along the edge, not the thickness of the board. Its a slight difference at 4/10.

I’m using my double bladed marking knife for illustrative purposes. Marking with ink is easy on the eyes if slightly less accurate than a knife line, but my joinery was tight in any case.

 

With the layout almost complete I started by beveling the bottom of the hopper sides so that they will sit flat. Beveling the bottom also removes the need to cut an annoying barb where the bottom edges of the sides meet, as well as making it easier to cut a bottom panel groove with hand tools.

 

With the bottoms beveled I finished marking the joinery. You know something is going right if your lines meet square across the beveled bottom edge.

Cutting the dado’s with dozuki and a piece of kumiko as a guide fence to my cut line. I start the saw with a stroke or two to get a kerf all the way across the cut, then take the guide away and angle the saw. Its good practice for dozuki technique. To keep the saw from jumping the kerf you have to saw flat.

Ahhh! So much easier to assemble with a little joinery, even if this thing is getting nailed together with pneumatics.

Once the sides were together I lopped the upper corners off. The angle for that cut is a further segment of the unit triangle, important when you want to cut mortise and tenon, but for a simple hopper like this I just flush sawed using the edge of the side as a guide.

I didn’t use a bottom panel groove, just beveled the edges to fit in the hopper a little above the bottom. Surely this is not as strong as nailing the bottom on to, well, the bottom, but it looks nicer to me.

If you want to make a strong nailed box or hopper its worth studying the prototypical Japanese style crate, this one’s for my drafting tools.

So there it is! Basic hoppers are not at all intimidating once you give it a try, and you will be on the road to some really awesome woodworking possibilities once you step outside the world of square boxes. I’d really like to make a rocking crib one day that uses a hopper and splayed legs!