I have not yet finished with the planning for the wheel - I know which wood I will use, I have most of the dimensions figured out, so there's details and unsolved questions left - like "how much tension will my drive band need, and do I have to build in something acting as a brace or stabiliser for the main upright".

Also, there's the question of how I am going to procure the strip of wood necessary for the wheel rim. In contrast to winding wheels or modern treadled wheels, the Great Wheel has a slim but wide, lightweight strip of wood serving as the rim. Which I can either cut out or plane out of a board with normal thickness, or try to buy, saving me the work. So next step in line: find out if there is somewhere near me where I can buy it, at an affordable price and with measurements matching my requirements (and then figure out whether the whole strip, uncut and not yet bent, will fit into the car).

As you can probably tell from the title of this blog post, I have decided to take a shot at making a Great Wheel myself. I am going to base its construction on the well-known Luttrell Psalter image which will result in a fairly big wheel, standing on fairly long legs, with an upright holder for both the spindle and the wheel.

In contrast to later wheels that are still existing, the medieval Great Wheels never seem to have angled uprights holding the wheel itself or the spindle. There will also be no threaded tensioners; I have yet to decide whether to add a different tensioning mechanism or to just tension by changing drive band length.

The whole thing, in any case, should be
a) done so it can be taken apart easily for transport or storage;
b) not use modern materials or concepts;
c) match the Luttrell wheel as well as possible;
d) function as a proper productive spinning tool.

So the usual, the usual. Apart from the tensioning issue, however, I think I have figured out most of the details - putting together of the parts will be done by using wedges, similar to how my table substruction is held together; the legs will be conical and thus should have enough friction in their sockets to stay in there when the wheel is carried around; the largest single bit will be the wheel itself, and that is non-debatable due to construction reasons.

I am very much looking forward to this!

Sometimes, it just takes a while for all kinds of things to turn towards favourable constellations... and it seems that I might get a shot at a portable Great Wheel, with a little luck and a bit of woodworking.

For those of you not familiar with a Great Wheel: this contraption (also called Walking Wheel or wool wheel sometimes) is the very early form of a spinning wheel - basically, it's a hand-spindle mounted sideways and connected to huge lightweight wheel by a drive band.

Image from British Library Manuscript Royal 10 E IV, f. 147. Dated to last quarter of 13th or first quarter of the 14th century. Link to the catalogue entry with more information.

There are a few common problems with building a wheel like that, especially when it's part of the intended use to lug the thing along to different events: It has to be properly functional, it should be correct regarding materials and construction, and it has to be possible to take it apart enough so that it can fit into the car. Add to this the fact that the images are not always very clear, or have a proper perspective, and that one can build a functional wheel much easier if one has worked with this type of tool already, and there's quite a bunch of difficulties. Plus it's of course necessary to have the wood, the tools, and the crafts abilities to make such a thing.

Well, some of the basic construction and concept problems sort of came up with a few solutions almost by themselves yesterday evening. A woodworking workshop is at the moment magically appearing in our basement, including a gadget necessary to steam-bend wood. There also is a little leftover wood. And I should be able to procure the metal parts for the wheel with little or no trouble, the way it is planned at the moment... so I will do some thinking, and some scheming, during the next weeks. And who knows, with a little luck and some dusty woody work... there might be another wheel in my future.

(Oh. You might have heard that saying about how spinning wheels are herd animals? It's totally true. If you do not want a herd of spinning wheels, you should keep your one and only wheel isolated. Don't get a second one. Don't even lend one from someone else for a while. They will start multiplying then. It's probably best if you don't even leave it alone in another room with a second wheel. They're almost as bad as rabbits. Really. I swear.)

I got up earlier than usually today and then sort of got gobbled up by lots of different small tasks (and lots of phone calls) - to the point that I totally forgot I had not blogged yet.

So, with ample delay, here's today's blog post...

You might remember the spinning for the Hallstatt narrow wares reproduction quite a while ago? This has been covered by the Standard, an Austrian newspaper, and the little (German) article is online as well - you can read it here. There's also a special exhibition about the project at the Naturhistorisches Museum Wien, and I'm looking forward to seeing it when I am in Vienna for the 3000 years of colour conference. So much nice stuff coming from that project!

Since I had some more little troubles with xmgrace yesterday, I used the Phone-a-Friend Lifeline and did just that. And thus got myself a nice little one-on-one, flesh-and-blood Grace tutorial.

Where I learned the following Two Rules for Getting Grace:
Rule one: If plotting or importing data does not work, you probably have a dumb user problem and screwed up your dataset. Which is easy to do - just add a line break at the wrong place, or leave a string in.
Rule two: When working with grace, pretend it's a jump-and-run game or an egoshooter - save early, save often, save lots of different versions. Grace has no undo function, and hitting the wrong button (or even the right button) at the wrong time can permanently screw up things.

I'm not sure whether there's a third rule - insist on grace being totally cool and a very good tool no matter how much trouble it can make - but I will find that out (probably).

For now, though, I know how to get stuff like this:


so I'm perfectly content.

My computer has now successfully turned into a schizophreniac computer - it can run Windows and emulate UNIX too.
Now I only need to get xmgrace running properly (there are still some issues with my data import), and I can finally get those graphs with Gauss fits that I need for finishing my evaluation, and thus my article, and thus my preparation for the next paper (I will speak at the 3000 years of colour conference).

It's probably best that I have no clue at all anymore as to how much time I have invested in the spinning experiment. When I started out with this, I did not believe this would become such a huge item in my life. (I know what I would do if I had to decide again whether to do it or not, knowing how much would come after it. I would say... YES.)

So... please excuse me while I reboot my computer and try to find out where the issue is... and then hopefully finally get those histograms.

It really, really is amazing what one can learn (and has to learn) just because of some spinning. I have learned on Thursday last week that Excel will find the median of a list of numbers by... choosing the value in the middle of the list. Which means that instead of finding the statistical median (half of the values are larger than this number and half of the values are smaller than it), it finds the number in the middle of a list. Thank you, Excel, I could have done that myself. By placing a simple link to the cell in the middle of the list. Because yes, I can count! So I worked on a little more, using the average instead, and grinding my teeth (figuratively speaking only, though).


In case you do not have your own version of a spinning experiment that you need to evaluate and analyse, and have no clue what I'm talking about: the average is made by summing up all numbers in a dataset and then dividing it by the amount of numbers. The median is the value in the middle of the dataset. Why do I want the median instead of the average? Median is way less vulnerable to outliers in the data. Case in point - let's assume we have a list of values that goes 1, 2, 3, 4, 100. Average is (1+2+3+4+100) divided by 5, which is 22. In contrast to this, the median of the same dataset is 3.

And Friday morning, I had a little private time with Mr. Google again, and I found out that yes, you can force Excel to get the statistical median. You can tell it to find the x-largest number in a bunch of cells. Which means that if you know how big your list of data is (I do) and see if it's an odd or even number of data (I do) and, if it's even, can divide said number giving the length by 2 (I do) and can make Excel calculate an average (I do) you can tell it to calculate the average between the two numbers in the middle of the list. Gotcha.

Oh, and I need the median... because after some fiddling and trying out and looking at data and getting brain-dead and trying something else, the most patient husband of them all and me came up with a possibility to give relative variations of thread thickness. Which uses a simple formula built around either the median (good) or the average (not quite as good). And now please excuse me while I try to get my now nicely-sized histogram bins into a good graph form.

Which will include giving my computer a split personality - because the programme I plot to do my plotting with is only running on Linux machines.