New to weaving.  Bought a 70 year old Structo tabletop loom and am using it to learnthe basics.

Looking at floor looms and reading comparisons on type the following keeps coming up.  Jack looms are good for both balanced and unbalanced weaving but counterbalanced looms are only good for balanced weaving.

Can someone explain the didderence in real simple laymans terms?

Is most weaving balanced or unbalanced?

Does this mean that a counterbalanced is quite limited in what it can do?

All comments are welcome!!

Comments

Fri, 02/26/2016 - 14:20

sequel (not verified)

Structo Looms are rising shed looms.  The selected shafts go up, the others stay down in the resting position.  Jack looms do the same.  The shafts at rest hold the warps in the down position, while the treadled or levered shafts raise the selected warps.  The warp at rest dips down to the heddle eyes, below the level of the back and breast beams.  Jack looms have any number of different ways to do this - pulleys from above or wooden levers from below the heddle frames.

Counterbalanced looms lower the selected (usually treadled) shafts while lifting the opposite shaft it's connected to, because they counterbalance one another.  Warps are lifted and lowered an equal distance.  The warp t rest is horizontal from back beam to breast beam. 

Unbalanaced weaves are called that because when most everyone was weaving on counterbalanced looms, when they would treadle 1 shaft against the 3 others the shafts would not balance evenly and the shed would be uneven top to bottom.  Not impossible, just a little tricky, depending on your loom.  Many counterbalanced looms have such large sheds it is unnoticeable.  Others require a little treadling finesse to even up the warps in the shed.

The other types are countermarche, which lifts and lowers every shaft independently, making some unbalanced weaves easier.  The warp at rest is horizontal from breast beam to back beam.  The last type is a true sinking shed loom.  The warps at rest are above the horizontal line from breast beam to back beam.  The selected shafts are pulled down by the treadles.  The Louet David and the Normalo looms are examples of this type, also called "reverse jack looms".

 

Fri, 02/26/2016 - 14:46

Sara von Tresckow

Actually, if one of the shedding types has restrictions, it is the rising shed of the "jack" loom. Because only half of the threads are lifted and put under more tension, the shed floor tries to stay firm through a dip or other means, but does provide uneven tension at the fell line when beating. This shed geometry does hinder some types of firmly beaten fabric - that works better on either sinking shed or any type of countershed loom.

 

Fri, 02/26/2016 - 15:59

Skrentner

Great information, but two things are still not clear.

I still don't understand the difference between balanced and unbalanced weave.

Looking at pictures of counterbalanced looms it seems that shafts 1 and 2 rise and fall opposite each other and the same for shafts 3 and 4. If your pattern called for shafts 1 and 2 and 4 all to be used in one pick is this possible?

Fri, 02/26/2016 - 16:49

laurafry

Yes.  Although I prefer to lower the majority of the threads, not raise them, if at all possible.  

Unbalanced just means an unequal number of shafts are used to create the shed.  For example, Bronson Lace plain weave is shaft one for one plain weave shed with all the rest of the shafts for the other plain weave shed.  If you have a 16 shaft loom, plain weave would therefore be shaft one for one shed, shafts 2-16 for the other shed. Ergo, unbalanced...

Sat, 02/27/2016 - 02:25

ShawnC

Yes, you can tie 3 shafts against 1. Here is a nice explanation on looms and their differences: http://glimakrausa.com/learning-looms-weaving/types-of-looms/