It didn't take me long to figure out that this skeleton tie-up......
.... (which I'd worked out here) wouldn't work with my countermarche loom. The problem? The way the treadles are tied up.
The above tie-up draft is for a rising shed loom like a jack loom. With this type of loom, the only shafts tied to the treadles are the ones which need to be lifted in order to weave a draft.
A countermarche loom on the other hand, creates a shed by lifting some shafts and lowering the rest. This requires all the shafts to be tied so that each shaft is activated (either up or down) for each shed. The above tie-up could be re-written for a countermarche tie-up, which uses X's and O's instead of shaft numbers.
O = rising shafts
X = sinking shafts
Not so easy to read, is it? Which is why I prefer working with rising shed tie-up drafts, which are easy to mentally adapt for a countermarche (CM) loom. In fact, almost any rising shed draft can be used on a countermarche loom, except in the case of a tie-up like that skeleton above.
Why's that? Well, suppose a shed requires lifting shafts 1 and 3 together. According to the above CM tie-up, treadle 1 (1st column) is tied so that it raises shaft 1 (indicated by the O) and lowers shaft 3 (indicated by the X). Treadle 3 (3rd column) is the opposite. So, if I press both treadles together, they counteract each other and I get no shed because I can't raise and lower a shaft at the same time!
I wish I could tell you that I was clever enough to figure out the CM skeleton tie-up all by myself, but I'm not. It was Madelyn v.d. Hoogt to the rescue! On page 79 in her The Complete Book of Drafting for Handweavers, are 8-shaft skeleton tie-ups for both countermarche and jack looms.
The skeleton tie-up for an 8-shaft CM looks like this:
The blank squares are not tied up! The first two treadles are for the tabbies, the second two are for the tie-down shafts, and the remaining are for the pattern shafts. Because the tie-down shafts are tied independently from the pattern shafts, it is possible to tread both at the same time.
All in all, the footwork is a little awkward, but I'm gradually getting the hang of it. Between that and keeping track of two shuttles, it may be a bit slow going, but I've never been a lightning fast weaver anyway.
Posted 27 Oct. 2008 at http://leighsfiberjournal.blogspot.com
Skeleton Tie-Ups for Jack Looms
Summer & Winter: Tie-Up
Comparing Looms: Jack & Countermarche