The tie-ups in the two previous posts are actually examples of skeleton or universal tie-ups. They are repeated here.
This ingenious tie up for 4-shaft countermarch looms is often called a skeleton tie-up. The treadles are tied up so that two or more are used to make the sheds. This is a way to make more sheds without tying up so many treadles, or to create the sheds you need when there are more sheds than you have treadles. Summer and winter tie-ups can require more treadles than you have, so a skeleton tie-up is often used. Check the internet for more information on skeleton tie-ups for countermarch looms as well as jack and counterbalance. Yes, you can make skeleton tie ups on all kinds of looms.
Actually the illustration is a universal tie-up, because all of the 14 possible sheds can be made with only these 8 treadles.
Do you see the difference? The terms are closely related but the universal will do everything. But the skeleton will be a tie-up with fewer treadles than the number of sheds required for a particular draft. Both tie-ups use two or more treadles together to create a shed. If you can’t figure out a skeleton tie-up yourself, you can look at Tim’s Treadle Reducer online. www.cs.earlham.edu/~timm/treadle/form1.php I tried it and it was great. I put in that I had 8 shafts, 10 treadles, and 12 treadles were required. Then a grid came up and I entered the tie-up in the pattern. And a skeleton tie-up was given using only 10 treadles instead of 12, sometimes using two treadles together.
This tie-up for 4-shaft jack and counterbalance looms is an example of a universal tie-up because with it you can make all the combinations possible using more than one treadle at a time. That means you won’t ever need to make a skeleton tie-up with 4 shafts for these two kinds of looms. That’s because you can make every combination you want using the four treadles, no matter how many different sheds are required.