Wednesday, May 19, 2010

moving on

So NSTIW reading a thread on "looking for a cart" on the medieval encampments list when up pops:

>Hi there.
>One of the best things I have seen about carts in the SCA is this blog.
>
http://mckennawerks.blogspot.com/2009/01/some-thoughts-on-wagons-for-sca-use.html
>There are plans. There is a description about making a cart and how to solve some problems. >There is some history on carts.
>I hope that this helps you.
>Cheers
>John of the Hills

Thank you for the compliment, John. This prompted me to go back and re-read this blog. Since last night it's had over 150 hits, so I guess there's some interest, and I'm thinking maybe I should continue it from where I left off.

I've had a lot of other irons in the fire this past year both mundane and SCA, and my irritations regarding the dog-cart and the A&S faire system have mostly simmered down, so I sorta feel up to doing this again.

Here's an older shot of the assembled cart. Since then I've added wrought iron parts for the swingle tree and hounds, and a drafting harness. We'll cover those later, for now let's get back to the wheels...

When last we'd met the wheel hubs were cut, rough shaped, and mortised and I was about ready to move on to the spokes. First, the hubs.

Once again the hubs were mounted in the hub fiddle and given another light sanding. There was some light checking from unequal shrinkage of the drying wood. This was expected. Drying billets of wood without checking is virtually impossible. If the checking had split through at one of the spoke mortises I'd have been screwed, but luck held and the checks are all minor and cosmetic. Eventually they were filled with homemade wood putty--sawdust (really fine dusty stuff from the spindle sander) mixed with glue. I know this method has been used since at least the 1700s. Though I've never come across a reference to a period piece having been filled in such a manner, it seems to me logical that if a period woodworker was faced with filling such a gap he would either cut small wedges of wood and drive them in or just ignore the checks, or stuff some oakum mixed with hide glue in the crack. We do know that in shipwrighting checks were filled with oakum/pine tar. Not having any oakum, and not liking the stickiness of pine tar, I went with this.

Wheel hubs check, thus hub irons (hub bronzes?) were put on the hubs. We have many of these found in wagon graves from the bronze age. To make them I went to the scrap pile and pulled out some 3" bronze fittings still soldered to some old drain pipe I'd pulled. Some work with the torch and the fittings were off, then the hub of the fitting was cut off with an angle grinder with a metal cutting blade, and cleaned up on the wire wheel.

Using the dremel with a coarse sanding bit I carved down the hub to slightly oversized (just enough bigger I had to use a hammer to start it). Then I took the hub outside, set the hub iron in place, put a piece of 2x6 over it and whaled away with a 10 pound sledge. Them suckers are on. Okay, were on. Some further shrinkage loosened one to the extent that I resoldered a piece of copper pipe in it, narrowing it and restoring the friction fit.The last thing to be done to prep the hubs for the spokes was to flatten a shoulder from the spoke to rest on (marked in red).

The mortises were labeled with roman numerals for the starboard hub and letters for the port. This is essential as the tenons are cut to fit a particular mortise perfectly, and when done will only fit that mortise. Once the hub irons were taken care of it was time to move on to the spokes. I mentioned earlier I had wanted to use green oak from a tree that came down in a storm, but the wood turned out to have been "beetled." So I eventually went with some seasoned oak from an old project. The first step was to cut out blanks (with extras). The center of one end was found and marked.

I made a jig to hold the spokes upright and square in the drill press and using a plug cutting bit shaped the round tenon that will go into the mortise of the felloes.



Once this was done the tenons were cut on the opposite end using the dado head on the table saw. These were all cut slightly oversize to the intended mortise and marked to orientation on the hub as well as the intended mortise hole.

I then made a jig to hold the spokes so a taper could be cut using the sliding compound miter saw.


The laser guide is a wonderful 'extra' to have on this sort of project. The front block used in the cuts is not yet attached to the jig in this shot.



This picture shows the second step. First, all the spokes had a taper cut on one side with all the blocking on the jig set "square." To taper the opposite side the the blocking already installed was left in place an the front block was reattached to support the angled side.

A decorative cove was then routed on the edges of the spokes. This gives them a lighter look, but has no structural purpose. I use a roto-zip with a 1/2" radius bit. The same jig as held the spokes for cutting the taper was used to hold them for this step. Finally the waste around the felloe tenon was cut off with a coping saw.

At point it was time to fit each hub mortise an tenon, a tedious and painstaking process involving innumerable dry fits and filing until each spoke required moderate taps of the mallet to fit snugly into the mortise and a good bit of effort to remove. For this part loose is bad. As the hub continues to shrink while drying the spokes will be held in place even more firmly.


Time for supper; the next post will cover shaping the felloes and finishing the wheels.


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3 comments:

  1. When last we met you mentioned that you *had* made the hubs, but there was no detail on *how* (unless there is a post I can't find).

    Enquiring minds want to know. 8->

    ReplyDelete
  2. Hi Doushkasmum,

    The hub construction is buried in the post "Back in the saddle again" from Friday the 13th, Feb. 2009. The last picture in that post is a rough finished hub in the "hub fiddle" being mortised for the spokes. McK

    ReplyDelete
  3. I am SOOOOO glad you came back to this project.

    Teresa

    ReplyDelete