Joy of Sectors II: Revisiting "The Arte & Misterie of Coopering"

You may remember this picture of a persnickety Perkins working the angles on a coopering demonstration.

With a bit of math and the able assistance of my consulting engineer, we determined that the eight perfectly-equal staves of my Mary Rose tankard needed to have 67.5 degree bevels so that they would align to form a perfect circle of watertight, oaky goodness.

This assumed if you didn't round off your tankard/bucket/barrel or whathaveyou that you'd have an equilateral polygon. All sides (eight sides in this case) were the same and would be worked with the typically-modern obsession with precision and symmetry.

As we discussed yesterday, that wasn't quite right. Coopers make their staves whatever width their wood allows and it's not always symmetrical and there aren't always an even number of staves. This is important since they were cutting wood straight from the log and doing a lot of their shaping with an axe. (Axes are awesome and speed up woodworking considerably, but they're not really precision instruments.)

All of which throws off my equation a bit. You could still figure it out, of course, but it just got a bit harder.

Part of the problem here is that I tend to think of barrels and tankards as segments of a ring rather than pieces of pie. I've been peeling all these apples, so let's make a pie.

Not a meat pie, you goofball, an apple pie.

Much better. (The ice cream's a nice touch, but we won't be needing it today so I'll just eat it and get it out of the way...)

Like a period tankard or bucket, the average pie slicing cook isn't going to make every slice exactly the same size. The piece for the baker is big and the piece for the kids are small. Also Aunt Agnes, who always says she's on a diet, but takes twice as much ice cream as everyone else.

The nice thing about this way of imagining a coopered vessel is that you could (if everyone can hold their forks for a minute) rearrange those pieces any way that you want and you'd still have a pie the same size as you started with. The pieces would all fit together no matter how you rearranged them in the pie plate.

But with coopering, you're starting with a pile of uncut sticks and an entirely imaginary pie that you're trying to craft out of thin air and oak. So how do you do this when you don't start with a pie?

Enter the Sector.

If you remember, at its simplest form, the sector is two straight pieces of wood hinged at one end. Pretty much exactly like a pair of dividers, except made of wood.

The geometry of the sector is devilishly simple: The two legs are equal, meaning that the legs will form an isosceles triangle. If you place it at the center of your imaginary bucket (or whatever you're making), it forms an imaginary piece of pie. If you want to make a ten-inch bucket (measured across the bottom) you just mark your sector five inches from the hinge.

That's the inside diameter of your bottom.

The second mark you see there indicates the desired thickness of the walls of my imaginary bucket.

Now, no matter where the sector crosses the the outer wall of your bucket, or how far apart the the legs of the divider have to be (to accommodate your rough-cut variations in stave width) the legs form the angle that you're shooting for. 

You found your stave bevel without writing a single number on a single piece of paper.

As you can see, this is also helpful if you decide to repair or knock off an existing bucket.

But wait, there's more!

It's not just a measuring device for finding the angle of your bevel either. It's also a jig you can use to monitor your progress as you create the bevel on your staves. Hold the bevel up to the stave as you work and align it to your marks as you go. 

The angle of the sector will tell you how far you need to lean the stave over as you plane the bevel. When the stave sits snugly in the sector between the marks, you're golden.

The importance of this cannot be exaggerated for the working cooper. And this is the part that I forgot when I was doing my demonstration.

I almost wish that building that bakery at the Washington Midsummer Renaissance Faire had been the first step in this project rather than happening in the middle. I suspect that I've fallen down on most of these projects simply because I'm thinking in terms of one-off bespoke items rather than the economies of production.

The practicing cooper isn't making one bucket at a time. This isn't bespoke bucketing on Bond Street, it's mass production because a cooper (and his apprentices) gotta eat. So if they're making as many buckets at a time as they can reasonably get away with, there's no room to be fiddling about with equations and making these exacting symmetries that we've become so accustomed to post industrial revolution.

A cooper's shop is making piles and piles of rough-cut staves and assembling them into a pile of ten-inch buckets and they all have to fit together no matter which bucket they're getting shoved into.

Yesterday I asked where I should stop. I don't know that I'm going to go back and repeat every experiment and demo that got us this far, but going forward I will certainly be taking a hard look at each of these trades and asking the question that should be obvious: How did they do this fast enough to make a living at it?

Because therein lies the real secret of most of these trades.

Now go eat some pie. You've earned it.

-Scott 

Postscript

The "Aha!" moment for this didn't come from thin air. (They never do, no matter what anyone tells you.) I've been reading about sectors recently, mostly using Jim Tolpin's books and articles so I was in the right mindset when I had the good fortune to catch an episode of Roy Underhill's "The Woodwright's Shop" featuring white cooper Norm Pederson who actually demonstrated many of the things that past coopers on that show had previously waved away as "something you learned with experience."

The episode is not available online anywhere I can find it, but you can download it for $3.99 from Popular Woodworking here: https://videos.popularwoodworking.com/courses/the-woodwrights-shop-s24-ep04-norm-pederson-white-cooperage  

Or you can buy the whole season on DVD like I did. I highly recommend it if you have any interest in trying this out yourself with better results than I had on my first outing.

Further watching...

This is not that video, but it's an excellent demonstration of white cooperage filmed at an outdood event, so the sound isn't always so great.

Thoughts from the peeler: The artisan obsession and where does it end?

There is in just about every artisan, a touch of obsessive compulsion. Whether or not it's a disorder depends on how you feel about being both obsessive and compulsive at the same time with sharp implements in hand.

I don't want to make light of a genuine medical disorder. As someone who suffers the black periods of lost joy and time that is depression, far be it from me to make light of someone else's affliction.

Obsession and compulsion exist on a sliding scale, which is set by the same people who have categorized an affection for coffee as a mental disorder.

So let's ignore those folks for a bit.

For all practical purposes, it boils down to whether your obsession/compulsion is positive or destructive influence on your life.

Be ye moderate in all things except moderation.

So it is with caffeine and beer and so too it is with handicrafts.

But where is that moderate line? When do I stop? How far do I take each of these explorations of a craft? When do I tie it off and call it good? Do I keep going until I've got it perfect? Is perfect the enemy of the good?

I discovered recently when I began exploring the uses of the sector, that I was wrong in a very important way when I discussed the many ways for finding the angle at which the staves of a bucket or tankard meet.

My methodology was modern. For one thing, we started with an equation. For another, it depended heavily upon looking at the tankard as an equilateral polygon and we did some really sweet math based on that assumption.

That was an inaccurate assumption.

Even though it worked.

As I examine more coopered buckets and tankards, it because clear to me that the old coopers didn't think that way. The staves of a bucket are rarely all the same size, and no two identically-sized buckets seemed to have the same number of staves.

My math was accurate, but my method was wrong.

The period method is really cool. It's easier. And it involves a sector and some different neat math having to do with isosceles triangles and dividers.

My assumptions were wrong and even my successful result was... I don't know. Was it a failure to achieve the goal by apparently modern means?

A period item was created, but it was based on best guesses made with a modern mind. My methods of arriving at that item were modern even though I used my best period tools to achieve the result.

I know all of this because I didn't finish exploring coopering when I finished writing about it. I kept going. I kept talking to other coopers. I examined barrels and buckets in antique shops. I made a bucket. Then I made a butter churn. Then I repaired some damaged buckets and barrels and tankards back to working order.

I know I was wrong because I didn't stop.

I made an ale pail that would hold ale, but did I succeed or did I fail.

Sorry, that was Seussical. Sometimes I can't resist.

At some point do I stop going back and adding to these projects?

Or is this exploration of artisans a reflection of artisanship itself in that the learning never actually ends? And if that's so, is my quest really impossible after all? Will I ever have more than the most surface knowledge of any of these crafts if I cannot devote more than the duration of a few blog posts to each of them?

How do I know when to stop?

And if I'm honest with myself, can I stop even if I want to?

- Scott

The Joy of Sectors: Getting our Galileo on...

"For the eye is always in search of beauty, and if we do not gratify its desire for pleasure by a proportionate enlargement in these measures, and thus make compensation for ocular deception, a clumsy and awkward appearance will be presented to the beholder."   

- Vitruvius, De Architectura 

Of course, a major part of the "rebirth" heralded by the renaissance was a revival of the mathematics and geometries of the Arabs and the ancients. By harkening back to the glories of their Hellenic ideal with their domes and pillars, the Renaissance brought with it a new and almost slavish devotion to finding the sacred in geometry and symmetry. Not just buildings, but furniture and textiles began to push painted, woven, and carved decorations to ostentatious heights.

I'm not particularly well known for being good at math and certainly didn't receive high enough marks in school to give one the feeling I would go on to write fluently about engineering and architecture. Thankfully, our typical renaissance artisan wasn't particularly well known as a mathematician either.

Please note that here I am drawing a line between the theory and the application of maths. Although the loftier theories may have passed him by, the practical maths of proportion and symmetry were alive and well in 16th century workshops. The average Elizabethan joiner may or may not have known who Euclid or Pythagoras was, but he could apply their theories well enough to please the eye and the customer.

We've discussed some basics of dividers before, when we were coopering. Add a sector and by their powers combined, you can accomplish an amazing number of tasks with very little actual number-crunching.

I first learned the magic of the sector in the same math class where I learned about the Fibonacci and the various permutations of the Golden Mean. Then I didn't think about it much for several decades.

Like most woodworkers, I've always kept a set of dividers. Dividers are handy for drawing circles and arcs for those fantastically symmetrical carvings I mentioned, also transferring dimensions from a ruler or a drawing to the wood. I've used them for laying out dovetails and for finding center and a host of other simple tricks.

But when they're accompanied by a sector, they can do much, much more.

My geometry teacher knew that the wickedly-sharp compasses we were equipped with as part of our standard kit were capable of more than stabbing us through our canvas bookbags. When paired with a sector, they could be used to accomplish great feats of proportion and scale

And she had no less a personage than Galileo Galilei backing her up on that.

I didn't care, I was nine; I wanted to draw circles and stab ants with the damn thing. Education is wasted on the young. Sometimes, I think adults should be required to repeat primary school periodically to pick up all the sharing and math and social studies that we missed, never mind the history. We seem so determined to keep repeating our history anyway, it might as well be in a classroom.

"I'm sorry, boss, I can't come in today, I have geometry class and then detention because I said I was thinking about voting for Donald Trump..."

Anyway... flash forward to a 2011 issue of Popular Woodworking magazine I picked up at the newsstand because of a cool cover article about Thomas Jefferson's stacking bookcases. Inside was an article by Jim Tolpin on the use of the dividers combined with a sector (see the video below) to derive a host of useful proportions and measurements for cabinetry design.

Like my teacher before him, Jim attributed the invention of the the sector to Galileo. I'm a big Galileo fan, going way back, and ere the end of things, we might even get into some of his experiments with optics because I enjoy that sort of thing.

Galileo's Sector displayed in the Putnam Gallery -- Image via Wikimedia Commons, Creative Commons CC-BY-SA 3.0

They were both likely wrong about the inventor. The basic principles were first proposed by Euclid and put to various uses since. It seems more likely that he was the Bill Gates or Steve Jobs of the late Renaissance. He was a technological entrepreneur who envisioned new and popular uses by combining existing technologies and concepts in unique ways. That said, who initially turned a compass into a more complex instrument matters little, because ere the end of the 16th century, the concept broke out in a Big Way in the manner that technological leaps always seem to.

The sector as Galileo created it is partly well known because of who he was, and partly because it was enormously successful as a commercial product. The sales of the instruments made his fortune long before he started tweaking the beards of the Inquisition with his planetary models.

Galileo primarily sold his sector as a military tool, an instrument which in addition to its more basic Euclidean functions carried additional scales useful for the gunner in the trenches.

I have no use at the moment for determining powder loads and trajectories. There just aren't that many armies out there right now that need that sort of thing done the old fashioned way. I will be making a simpler, significantly less schmancy, workingman's sector along the same lines as Jim Tolpin's.

If nothing else, I have a lot of period carving and surface decoration on my project list, so we can look forward to seeing great granddad's dividers and sectors come out for that.

And for now -- since sectors weren't all that widely used until the 17th century anyway -- that will be the soft limits for our use for the things. I'll make a couple in different sizes and we shall see what use can be made of them without gunpowder getting involved.

That said, the Honorable Artillery Company was knocking about, but they weren't really what you'd call a trade guild. Nevertheless, I picked up a copy of Galileo's instruction book that was sold alongside his sector because you never know when you might need to hit something a long way away with a ball of something fired out of a tube full of grey powder.

- Scott

Sewing leather revisited - Making a sheath for my Frost Mora carving knife

Historical Note: I'm not sure who made the knife sheathes. There's no 'Scabbard Company' on the livery rolls in the 16th century. Possibly the Worshipful Company of Girdlers or they were a sub-group of the Leathersellers, who handled most of the miscellaneous leathergoods that made up Elizabethan life. It might even be the Cutlers, who were responsible for all the other bits and bobs associated with knives. Any way you cut it, there were a lot of knives in Elizabethan England. Every knife needs a sheath and mine are no different.

Looking at the projects that have been collecting dust, I think the shoes are probably the most annoying thing to have lingering overlong in the workshop. For one thing, the leather and lasts and tools take up a lot of room and for another, I just really need to get them done because I need a new pair of shoes. (Also, I hate leaving things half-finished.)

Unfortunately, while I haven't been completely idle since I parked this project in the driveway awhile back, I also haven't been doing any leatherworking. Cordwaining involves some pretty heavily-developed leatherworking skills, especially sewing, so I need to practice.

You might recall the costrel project, which is a study in heavy-construction sewing techniques. I also need a practice project that uses some of the more subtle stitches and techniques for closing the uppers of my new shoes.

As it happens, my preferred style of knife sheath uses the round stitch to close the seam up the back. And since that's a fiddly piece of business to learn and I'm in need of practice, methinks I hear a knife calling for a new leather home.

My favorite woodcarving knife has to be this Swedish blade made by Morakniv simply called "The Woodcarving 106". They sell on Amazon for about $25.00, which is a pretty good price for a knife you won't want to put down.

It's a strong little workhorse and can hold an edge like nobody's business. You couldn't ask more from a knife.

The problem: they come with a crappy plastic sheath. And that just sucks on a deeply aesthetic level.

The solution: make a new one, of course.

Parts List:

• A knife
• 2 poplar scraps slightly larger than the knife blade
• Shaping tools for wood (knives, spokeshaves, rasps, files, sandpaper... etc.)
• A piece of vegetable tanned leather large enough to wrap around the knife
• To make the pattern: See this post about patternmaking
• Wood glue
• Quality, long-staple linen thread
• Two large-eye long darning needles (or boar bristles if you can get them)
• beeswax
• sticky wax (if you have boar bristles to use)
• Stitch marking wheel or ruler
• curved awl 

A truly razor-sharp knife will eventually cut its way out of any all-leather sheath or die trying. If you make a standard sheath by sandwiching the blade between two pieces of leather as we used to do in Boy Scouts, the knife has an even easier time of it because it can just slice the stitches. Some leatherworkers use rivets instead of stitches and that's fine, but hardly traditional.

First, some woodworking...

I prefer wood cores (of course), so step one is to make a wooden house for the blade of the knife. I used a bit of poplar I had lying around, but any hardwood will do. We're going to use two pieces with a knife-shaped void between them to house the blade.

Cut two pieces of wood, slightly larger than your knife blade. Trace around the blade of the knife on one side of each piece of wood.

Use chisels and a router plane to remove the waste from one side (and one side only) leaving a void where your knife sits flush with the wood, like so.

 It doesn't have to be beautiful, but it needs to fit.

Why did I carve only one side of the sandwich? Because in any joinery project, it's unwise to leave a wedge (like a knife blade) sitting against a seam. You're just asking to get that seam split apart.

Glue your sandwich together using the glue of your choice and clamp it gently while it dries (or use rubber bands as I have done). 

You can use hide glue for the period touch. For knife sheaths, though, I prefer Tightbond III because it's waterproof and I'm more concerned about rust than turning out a period-perfect piece. This isn't really a reproduction of a period piece anyway, though the techniques are sound and were used during our time frame in this capacity.

Note that my pieces are rather thick. Partly that's because I'm using a scrap and partly it's because I wanted lots of room to maneuver when I got around to shaping the glued-up piece. 

Let it sit overnight to cure.

Make sure the knife sits securely in the void you carved out and then use spokeshaves, chisels, rasps, and handplanes to cut it down to the bare minimum of wood. I left roughly 1/8 inch of wood on every side of the knife blade.

Seal the wood. You can use an oil finishes for a period-appropriate sheath, or you can cheat and use polyurethane like I did. The next part of the process will expose this wood core to the damp and my woodworking often takes place out of doors in less-than-ideal conditions. It's your choice. 

Insert the knife into the wood sheath and wrap it in paper and masking tape as we did when making the pattern for the shoes last year. Note that the sheath goes about halfway up the hilt of the knife. That's on purpose. It helps protect the knife and will keep it from slipping out of the sheath quite so easily.

There's only one seam, up the back, and the edges should just meet. For more information on this style of patterning, see this post here: Wrapping Peasants - Pattern Drafting Part I and this post here: Drafting patterns for leatherworking.

Note #1: Remember to decide how you're going to attach it to your belt before you get to the cutting leather stage.

Note #2: If you want to incise, tool, or otherwise decorate your leather, do so before you begin sewing. I admit that I have at least once forgotten to do that. For tools like this one, I like mine a bit plain.

This is where we begin practicing our cordwaining in the guise of sheathmaking...

Boar Bristles and Closing Awls

Waxed Ends (skip if you don't have boar bristles/just want to use needles)

I'm going to sew this up using boar bristles instead of needles. This is the period-appropriate method of work for shoemakers and bookbinders. The sharp, flexible bristles are attached to the end using sticky wax and cleverness. I'm rubbish at it and need lots of practice, but Francis Classe is great at it and provided us with a great tutorial on how to go about it.  I do a lot of reinventing the wheel on this project, but I can't best Francis at something that he taught me, so if you want to go the bristle route, you should follow that link and learn to do it right.

Some modern shoemakers have good luck using heavy-test fishing line in lieu of the boar's bristle. If you don't have access to a boar or its bristles, there are those who swear by it. I've never tried it, though, so I trust your Google-fu to let you figure it out. I tried to find a link to a tutorial I could share but only found references to a dead site.

Your mileage may vary.

Why boar bristles and fishing line?

We're going to perform something called the "round stitch" which follows a curved path through the leather. In order to pull that off, you use a curved awl to create a tunnel through the leather from the top to the edge. Then, you need to be able to push your 'needle' through that tunnel. 

You can do this with long, slightly flexible needles like long darners and I've had decent luck doing so in the past, but a piece of sharp, flexible, keratin like a boar bristle or a similarly flexy bit of fishing line are a godsend and speed things up.

I'll get more into the boar bristles and waxed ends when we tackle the actual shoes. This is really just a test run...

Curved awls

The two outside awls are the same as in the previous photo. They are made from antiques, which I bought from the extra stash of a cordwainer friend of mine. You don't have to haunt antique stores and bug your shoemaking buddies for their tools, though. These closing awls are still sold new by some specialty retailers, or you can get by with that middle awl with the knurled piece for changing the blades. It was purchased new from Tandy Leather, just last year. Just make sure the cross-section is oval rather than round to prevent tearout.

Closing: The Round Stitch

Use your marking wheel (or a ruler, dividers, etcetera) to mark an even stitch distance all around the edge of your seam on both sides, 1/4 - 1/8 of an inch back from the edge. 

Make sure that the marks on each side a exactly parallel to one another.

My depth is wandering quite a bit here. You can see why I feel like I need the practice.

Use your curved awl to create a hole that angles from the mark made by your stitch marker curving toward and out the edge of the leather. The depth should be just a bit deeper than half the leather's thickness. THIS TAKES A BIT OF PRACTICE. I'd advise using some scraps to practice.

Too deep and your seam will pucker. Too shallow and you'll tear out.

Al Muckart -- a reenactor and craftsman who writes the Where Are the Elves? shoemaking blog -- created a tutorial that illustrates quite well how to do this. I've linked to it in the footnotes at the bottom of the post.

Wet the leather in warm water to make it a bit stretchy. You don't want to soak it too long or to use boiling water. This is not "cuirboulli", which would be too stiff for this particular purpose. Just hot tap water is fine and don't soak it for too long. (You just want it pliable and a bit stretchy, but don't want to leach all the collagen out of the leather.)

Roll the leather between towels to get the excess water out and then wrap it around your wooden core with the knife still in the sheath. Oil the blade and seal the wood and you should be fine for the amount of moisture we're talking about, but now you know why I sealed my wood. (Some sheath makers wrap the knife in plastic wrap, which isn't a bad idea.)

Either create your waxed ends or thread two flexible needles on either end of a piece of strong hemp or linen thread. I stipulated "long staple" which refers to the length of the fibers that were spun to create the thread. The longer the staple length, the stronger and more durable the resulting thread.

Working from both sides at once, sew back and forth across the gap. Note: people who make puppets and stuffed animals refer to as a "ladder stitch" while other leatherworkers may call it a "butt stitch". Shoemakers call it a round stitch, so we're going with that from now on.

The rest is stitching and letting the leather dry.

That open end is on purpose. It's traditional for to leave that little curled fishtail on Scandinavian knife sheathes.  I'm not sure if there's a practical purpose to it other than making the sewing easier because you don't have to ease the pattern around the point. It will be cut back a bit when I'm finished.

A lot of Nordic fishermen settled along the coast in Washington state, and I've seen antique fileting knives that have sheathes like this where the tip was cut to a little fishtail shape.  I'll just be slicing mine off at a pleasing (to me) angle.

Yes, that's blood on that bit of tissue you see above. Remember to respect sharp tools. And remember that the sharper the tool, the less damage it does when it does cut you. 

Now we just have to let the leather dry, then dye it to our desired color and finish it with a bit of wax and polish.

Further Reading:

1. Cordwhatnow? A layman's guide to shoemaking tools & terms School of the Renaissance Artisan, posted January, 2014
2. Basic Techniques of Construction (Including waxed ends and how to use them)
   by Francis Classe at his Raised Heels cordwaining blog
3. The Round Closing Seam in Shoemaking (PDF)
   by Al Muckart of the Where Are the Elves shoemaking blog

Drafting patterns for leatherworking

Note: This post isn't really about 16th century methodologies.

I've shared a few of my favorite "hacks" (as the kids say) for making leather items with a bit of improvisation in the tools department. We've used flower pots to build mugs, we've used butter knives for skiving, and my favorite cheap woodworking chisels for cutting.

So let's talk about pattern making.

If you've ever followed my maskmaking tutorial or done any other leatherworking without a pre-printed pattern, you've noticed that there's often a size discrepancy between any paper pattern you've created by wrapping the item in paper and marking seams (as we did with this shoemaking post) and the leather you're going to use.

This can cause some real fit issues.

The problem stems from the difference in thickness between paper and leather, combined with the fact that paper doesn't stretch around a form and leather does. You could use some math to account for the thickness, but the stretch is a bit more difficult to guess at, which can result in some wasted materials.

Here's my Not Even Remotely Period (NERP) approach to leather patterning that saves me a lot of time and leather when I'm winging it with a pattern: craft foam.

In the image below, I am preparing a knife sheath for one of my carving knives. I've wrapped the knife in paper and marked the seam, but to get a better handle on the actual shape of the final piece of leather, I made the pattern in the back on thin white foam which I purchased from a local Michael's craft store.

It's not quite as thick as the final leather, but it's close. More importantly, it stretches a bit in a manner that is very reminiscent of damp leather. And since this is a pattern where the fit is precise and the seams have to just meet with no seam allowance, fit is so very crucial.

It's NERPy, sure, but it works a treat.

- Scott

Tools of the Trades: Dumb as a...

I don't know if it's a real memory or something my adolescent brain concocted after the fact, but I remember a day when my grandpa swore that something or someone was "Dumb as a bag of hammers." Being a kid that took an inordinate amount of joy from the tools grandpa let him use, in the memory I told him I didn't understand why that would be dumb. I couldn't think of anything better than a Whole Bag of Hammers!

I'm mostly suspicious of the memory because it makes me sound rather more precocious and clever than I suspect that I really was. It's one of the oddments of life that you can't always trust your own memories, but there you go.

Be that as it may, I still get an inordinate amount of joy out of my tools. And now that I actually have enough hammers to fill a bag, I can tell you from the bottom of my heart that this apocryphal memory holds a kernal of truth: There really aren't many things cooler than a Whole Bag of Hammers.

I suppose that some of you are, quite correctly, pointing out that there's also a half dozen mallets in that bag. All the same, there are enough hammers to make the bag rather heavier than I'd like to tote around.

For the record, this isn't an example of excess. Each of those hammers (and mallets) has a specific purpose to which it is best suited. It is enormously frustrating to me to watch someone use the wrong hammer for their task. Or, worse yet, to use something else like a wrench in place of a hammer.

My wife thinks I need to seek professional help.

Believe it or not, there is a distinct difference between a claw hammer, a rip hammer, and a ball peen hammer. The face of each hammer is shaped to best suit the task for which it was intended, and the temper of the metal as well. Try to form metal with a claw hammer and you'll get a good idea why you shouldn't, no matter what Jamie from Mythbusters might wish you to believe. Will a hammer explode on you if you're using it wrong? No, that's a bit silly. But you will expend more energy than you would if you went to the toolbox and got the correct tool.

It's difficult to choose favorites, but if you put my feet to the fire, I think the shoemaker's hammer you see above is my favorite. Aesthetically, it's just intrinsically pleasing. Like the distilled cartoony ideal of the essence of hammerness. It's shape and the domed face are designed for shaping shoeleather, condensing the leather and forcing it down over the last without damaging or marring the finish.

The horn hammer underneath it is also a leatherworking tool used by mask makers for much the same purpose. The point of the horn forces leather down into the voids of the mask matrix as it condenses and hardens the leather. This also has the charming effect of dimpling the leather, giving the mask a characteristic look you can't get otherwise. 

These mallets serve various purposes. Top is a felloe mallet. These were originally used and made by wheelwrights, who would cut them from old sections of wheel. These sections are properly called "felloes". Pop a handle on it and sell it to your fellow craftsmen and you've got a lucrative sideline. Like most woodworkers, I use mine for carving and whacking chisels.

Next one down is a rawhide mallet. That head is made from rolled rawhide leather that has been varnished into a nice, hard, mallet head. The resultant head is hard enough to drive a chisel if you've a mind to, but not hard enough to knock a dent into wood. I bought it to use on leather tools, but since I rarely tool my leathergoods, it's mostly used in cabinetmaking.

The two gavel-looking mallets are also for cabinetmaking. They're used to knock together mortise and tenon joinery and also to set the blades in wood-body planes. I'll discuss those a lot more when we're in the joinery section of the project.

Of course, these are but a few of the mallets and hammers I'll use in the course of this year. Ball-peen hammers, blacksmithing and sheet metal hammers, even a mason's rock hammer. All of them serve a specific purpose, and have evolved over centuries, even millennia, into their current shapes.

So give a care to the humble hammer and choose the correct one for your task. Both you and your project will thank you.

Oh, and keep them in a toolbox. Don't keep them in a bag. Because grandpa was right; that is kinda dumb.

~Scott

My Staves Are Numbered: Making a Mary Rose Tankard Part Four

I forgot to mention one of my mistakes in that last post, but that's okay. I didn't need to dwell any more than I did and thankfully, it's not like hide glue wasn't available in the 16th century*. Oak is a cantankerous wood and tends to be ultra-dense and sturdy except when it isnt, and when it isn't, it tends to be at the worst possible moment.

That chunk missing from stave #8 is not intentional. It's the result of a slipping chisel and a fault in the oak that was just ready to slip.



It will be repaired after the tankard is fully assembled.  Which brings us to numbering the staves. It almost seems logical to just number them one-through-eight, but that ignores an important fact of handworking wood: each side of each stave is different.

So, as you're fine-tuning each stave to match up to the one next to it, it's important to number the joints rather than numbering the staves.

Stave 1-2 matches up against 2-3, which matches up with stave 3-4... etcetera.  On the bottom, that means numbering the points of the octogon. The bottom too will need to be individually trimmed and scraped to fit into the croze.

The tension of the wood as it swells (as it will when it gets wet) will push against the hoops, which will push back and that tension will seal up any miniscule gaps left.

And that's how coopering works!

I hope.

Anyway, as you can see, every piece is complete. You can see in the picture above, the lid and handle are complete and it's all ready to go. Come what may, leaking or not, this ends tomorrow.

~Scott

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*Speaking of 16th century glues, I was recently gifted with a copy of "Il Libro dell'Arte" (The Craftsman's Handbook) by Cennino d'Andrea Cennini by one of my readers. For the record, I don't court such random acts of generosity but I approve of them wholeheartedly. Thank you Noel Gieleghem for the kind gift and your support past and present. I have already put it to good use!

The Arte & Misterie of Coopering: Making a Mary Rose tankard, Part Two

This being the part where we turn math into a drinking vessel...

You may remember this bit of algebra from last week. Contrary to what I've been seeing on an alarming number of YouTube videos and woodworking forums, it's the way to find the correct angle to cut your bevels on the staves of your bucket/tankard/butter churn, or whathaveyou.

n = the number of staves you want in your vessel.

And it doesn't change no matter how big or small your vessel gets.

There seems to be a lot of confusion about that out in the Interwebs. The angle is the same whether you have a diameter of ten feet or ten inches or two inches. For an octogon (or an eight-piece circle) the angle for the cut is 67.5 degrees.

Geometry is awesome like that.

The mystery of the bevel solved, it only falls to us to decide how to cut that angle accurately. As I said in the lead-in to this project, every source I have just says "the cooper eyeballed it." And the tool they used for that eyeballed angle was a big jointer plane mounted upside down on the floor of their shop.

You can see one being used in this engraving from my muse and tormentor Jost Amman. That's one seriously large piece of equipment. I checked around and those things are expensive even if you make your own (mostly the cost of getting the blade made).

Image source: Wikimedia Commons
Cleaned-up digitally by yours truly.

You can see it in use in this video I posted the other day of Ramona Vogel, journeyman cooper at the Colonial Williamsburg living history village: http://vimeo.com/11313428 I think that beyond some basic geometry, the real "art and mystery" here is how to finagle the right tools to make it all work.

Thankfully, the woodworking blog I got that video from (The Village Carpenter) came to my rescue once again with this post about a friend of hers who makes buckets.

He doesn't use a huge floor-mounted jointer; he uses a hand plane mounted upside down and it seems to work just fine. He also uses a jig, but I wanted to try my hand at this "eyeballing" thing that everyone seems so impressed by, so I grabbed my largest bench plane and a handful of clamps and my eyeballs this is what I ended up with...

I've already leveled the sole of the plane, now I'm making some fussy adjustments on the blade.

Taking the first few swipes across the blade.

Note that I'm wearing a glove on my pushing hand and keeping my fingers well back. I want to keep my fingertips on my hand and not on the ground where they'd get dirty and I'd have to hire someone to sew them back on...

Thankfully, the upside down plane worked a treat and I didn't so much as trim a fingernail on that razor-sharp blade that made such short work of that dense oak stave.

Take another look at the Mary Rose tankard we're imitating here and you'll note that the top is narrower than the bottom. Sort of an inverted pint glass shape. So I have to not only trim a bevel on either side of each stave, I needed to make each stave slightly smaller at the top than at the bottom. 

Forgot to mention that I also made it thinner when I was shaping them on the shaving horse. The intent being to give a more substantial foot to this thing since it's going to be quite tall and on the rolling deck of a ship no one wants to spill their beer.

The tool I'm using to check the angle in the photos below is called a sliding bevel.  I pre-set it to the correct angle and locked it off. I've only to hold the piece up to the light and slide the blade of the tool along the wood, watching for gaps.

  

I tried to find out how they did this in the 16th century. A lot of tools like dividers and the like predate the period, but I can't find anything concrete on the topic of the sliding bevel. If anyone has anything on this, I'd love to hear it.

The results are eight staves, evenly shaped to form a circle which will, under compression from its hoops, swell to become water-tight.

It's almost but not really discouraging to note that if you have a sliding compound miter saw, a couple of router bits, and a table saw, this project really would take you an afternoon. But it wouldn't be nearly as cool as this one.

Or so I keep telling myself...

Still a lot of work to do with the scrapers on the inside and quite a lot of fiddly work aligning the staves and making everything work out just right.

Then I can make a handle and a lid.

Note: Don't worry, it only looks like I'm behind. I'm also learning to knit, making a leather bottel, and getting started on hornwork.  More updates on all that stuff later this week... I hope. 

~ Scott