All looms have limitations. The most frequent limitation we hear discussed is about the number of shafts a loom has available . . . no matter how many we have, every once in a while all of us seem to want a few more. But, just as challenging is the possibility for looms to run out of treadles.
For a modest four-shaft loom, there are a total of 14 possible ways to tie-up a treadle as shown in the image below.
Tie-up possibilities for a four-shaft loom
I have yet to see a four-shaft loom with 14 treadles (although, I know of one in LaConner, WA that has 12). If a treadling sequence for a particular pattern requires more treadles than the loom has, it’s easy to do a direct tie-up. This means treadle 1 is tied to shaft 1, treadle 2 is tied to shaft 2, and so forth and so on.
Four-shaft direct tie-up
To treadle a direct tie-up, one or more treadles will be stepped on for each weft pick as shown in the following image
2/2 twill treadling on a four-shaft direct tie-up
Another approach that may be possible is to tie-up the treadles as a “skeleton” tie-up. This is similar to a direct tie-up because weaving may require more than one treadle to be stepped on for a single weft pick . . . however, a skeleton tie-up differs from a direct tie-up since more than one shaft may be tied to a treadle. Below is the most common skeleton tie-up I use when I weave double weaves on a four-shaft loom.
One way to tie-up and treadle a four-shaft double weave
All of this is manageable on a four shaft loom; however, things get a little more complicated when more than four shafts are involved. It becomes easier to run out of treadles when one considers that there are over 250 possibilities for tying up a treadle on an eight-shaft loom . . . over 65,000 possibilities for a 16-shaft loom . . . and by the time we move on to 24 shafts, there are nearly 17 million possibilities. Looms, rooms, and hips are definitely not wide enough. So, what’s a weaver to do? Imagine if an eight-shaft loom only had eight treadles . . . How could the following be treadled?
Eight-shaft, 10-treadle sequence
Well, would a direct tie-up be possible? Probably not for this particular example. Why? The direct tie-up treadling sequence for the above 10-treadle sequence shows a weaver would need up to four feet at a given time for some picks.
This is an opportunity for a skeleton tie-up. There are two challenges when figuring out a skeleton tie-up. 1) Determining whether a skeleton tie-up is an option, and 2) If a skeleton tie-up is possible, what it looks like. This is where my latest “favorite things” comes in handy in helping make the process easier and faster . . . Tim’s Rudimentary Treadle Reducer http://www.cs.earlham.edu/~timm/treadle/index.php. This is an on-line tool available to aid weavers in figuring out whether a skeleton tie-up is possible and if so, dissecting the original tie-up into fewer treadles.
First, enter the number of shafts and treadles for the original draft and the number of available treadles on the loom.
Next, enter the tie-up for the original draft.
Within seconds, it will give you one of two results. It will confirm if a skeleton tie-up is not possible. If it is, it will provide an alternative skeleton tie-up.
10-treadle tie-up reduce to eight treadles
It will also provide the reduced treadle equivalent for the skeleton tie-up. In this particular example, each pick will require two treadles to be stepped on for each weft pick.
Unfortunately, not all drafts can be reduced into fewer treadles and woven with a skeleton tie-up. But, this is one of the reasons dobby mechanisms are so helpful.
In the meantime, I would like to publicly thank Tim McLarnan, Tremewan Professor of Mathematics who developed Tim’s Rudimentary Treadle Reducer http://www.cs.earlham.edu/~timm/treadle/index.php. It has saved me a great deal of time and numerous moments of aggravation.