Friday, February 13, 2009

back in the saddle again

This is me down in the McKennawerks (just kidding, I have a beard, but I really do wear a period hat like that)

Ok, the wagon building has suffered from:

1) shop waaaay to cold to work comfortably--long sleeves and power tools are not an auspicious combination.
2) every horizontal surface in the shop buried under wood and widgets.
3) sprained left elbow loading firewood.

But we've had some spring-like weather, so I was able to bring a little order to the McKennawerks, and it's time to get some work done. I'm putting the finishing touches on some wheels for the "buckboard" style wagon (the bed parts are still buried). Eventually (hopefully soon) I'll get some pics and description up. But I've gotten sidetracked.

A sidetrack with a deadline.

As I said, at some point I'll come back to the wagon, but right now I'm into building a period dog cart for an A&S entry. Since I have to do a buncha documentation for the entry, what could be better than to blog that? Why a dog cart when I don't own a dog? Funny you should ask... I'm once again attempting a Pentathlon, and the only logical entry I have for one of the divisions is in the category of "Animal Accessories." I figure this ought to be a pretty over the top "accessory."

First some commentary. This is an advanced project, and I'll be using some tools you likely won't have, I'll mention some alternative methods, and I'll be showing an alternative to a lathe for 'turning' the wheel hubs. And we'll also be (probably, possibly, maybe...) be making a spring-pole lathe at some point. And once again the plans will come last, as this is pretty much a 'figure it out as you go along' project.

When it comes to period dog carts we don't have a lot of information available. There are some period sources that mention using dogs as pack animals and mention dog carts, but I've only been able to discover one period illustration of a dog cart. It is reportedly in the 14th century illuminated manuscript called the Smithfield Decretals. It is on folio 110 verso of British Library Manuscript: Royal 10 e IV. Apparently this is no longer available on-line, but I have requested a copy from the British Library Image Search, and hopefully I'll have one early next week. And as I've mentioned before, we have very little in the way of extant cart or wagon parts from within our period (600 to 1600 ce). Thus we are left with the need to make logical conjectures.

So let's conjecture: First, most of the construction will be in "green" (recently cut) wood.

For several reasons. The first is that the wind and ice storms we had recently took down several trees near the house, so I'll be making use of a readily available material. Second, in period, most wood working was done with green wood until late in period. Green wood works easier. Using seasoned hardwood was a late period development--when tool steel that would keep an edge longer was more readily available. Thirdly, as the green wood dries out and shrinks it naturally makes the joints tighter. This is a definite advantage for the spokes and hub mortise and tenons.

Forth relates to the nature of the cart itself. Who would use a dog cart? Someone with a dog. What would they use it for? Hauling moderate loads within a walking distance of their home. It seems to me unlikely that a dog cart would have been an ornate capitol investment of a wealthy landowner or noble. More likely it would be simple equipment found at a monastery or large farm, and chosen as less of a capitol investment than a large horse/ox cart or wagon.

Though "Of Englishe Dogges" (1576 ce) mentions that the "Tinker Cur" was used by traveling tinkers to transport tools (and presumably goods and personal items) I think an itinerant use of a dog cart less likely, as the dog needs to be fed, and on the road this presents an expense/ difficulty that would exceed the transport value of the dog cart.

So for our purposes we'll assume a monastery dog and cart.Since the iconography of dog carts is limited, it is logical to extrapolate from images of hand carts and horse or pony carts of the period. shows an image of a farm cart driven by a monkey from the Lutrell Psalter (circa 1325-1335 ce). If we look at this picture we see a two wheeled ladder bed cart with wattle (basket weave) sides. This will serve as our inspiration piece.

I think it reasonable to assume our cart would be lightly built, and have a frame of green wood, joined with lap or dovetail joints and secured with trenails, and a wattle bed and sides. The harness would be of leather, with cast brass or pewter fittings. The value of iron would limit its use to where a suitable substitute is not readily available. Thus only the wheel hub stock rings and axle pins would be iron.

We're going to begin with the wheel hubs. These are in red oak. An oak of suitable dimensions was brought down by a larger pine during a storm last week.

Step one is to cut a billet of (hopefully) knot free straight trunk at least one foot above the roots, which will provide a nice even straight grain.

To digress. I don't own a lathe. Weirdly enough despite all the other tools I've picked up over the years I've never gotten around to buying one. So what we're going to do is make a hub fiddle--a jig (OK, technically a fixture holds a workpiece and a jig holds a tool, we'll stick with the linguistic barbarism of calling them jigs) a jig to hold the billet centered while we use other tools to shape it. If you look at the picture you'll see it's basically two support pieces with pins clamped to a workbench.

Across the top is a slotted board to support the tools over the top dead center of the billet.
I used a roto zip with the routing attachment with a 3/8 straight cutting router bit to shave the rough billet into a cylinder 12 1/2" long and XX inch in diameter.
I also experimented with using a dremel with a 1/4" routing bit in a jig. The dremel is mounted in part of a circle cutting jig which is attached to a simple sled to let it slide along the work bench top. This worked, and if I didn't have the rotozip I would have stuck with it but it was too darn slow.

I then marked up the cylinder with reference marks to make two hubs. The hubs will be separated after the coves are cut. I'll do this on the miter saw so that I get nice square cuts.

In order to turn the coves I used a trick usually done on the table saw, but here carefully done with a circular saw. The saw is set so that the blade is slowly lowered at a slight angle to the centerline of the cylinder into the workpiece which is turned by hand and the angled blade carves out an ellipsoidal cove.

Here you can see two guide blocks screwed to the top of the jig to accurately position the saw.

This is the cylinder marked for cutting into two hubs on the miter saw.

After cutting the hub blanks the ends are sealed with paraffin to prevent them from drying out too fast and checking (cracking). I also recommend storing them in the fridge until you're done working them to slow the drying process.
I then drilled them with 1 1/8" holes. To do this the centers are marked with a center finding gauge and drilled in each end with forstner bit on the drill press to create a hole trough the hub for the axle.

I then made another smaller (shorter) hub fiddle and mounted a hub on a 1 1/8" poplar dowel so that it would rotate freely and slide from side to side in the jig.
A word about dowels... just because the label on your dowel says 1 1/8" don't expect that it will be accurate, you made need to sand the dowel smaller or the hole larger. The dowel mounting is temporary, remove it as soon as you're done working on the hub, or the hub will shrink--locking it so securely in place you'll have to drill it out.
I mounted it to the hollow chisel mortiser. I stepped off six equal divisions with a pair of dividers then cut 1/2" x 1.5" mortises into the hubs. The sides of the mortises are parallel. Only in very heavy wagons with large wheels is it necessary to taper the sides of the mortise. In the case of these light duty dog-cart wheels the spokes will rest on shoulders above the tenons. But we do need to cut the tenons very tight because they are held in by tension only: no glue.

Here the mortises are being carefully cut with the mortiser. The tape on the chisle shows when I've cut deep enough (about 1.5"). Cutting into oak is hard and there's no need to overdo it.

After that it's off to the drum sander to clean them up a little. Tomorrow we'll dress up mortises and cut the spokes from more of the red oak. I'll also take some more detailed pics of the jigs.


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