Every weaver want the widest possible shed, and when more than one shaft is treadled a consistent shed with all warp threads raised or lowered by the same amount. This makes throwing the shuttle much easier, as it is less likely to snag or dive below the warp. These instructions apply to both top-of-the-lamms and conventional tie-up for a countermarch loom. They don’t apply to jack, counterbalance or computer controlled looms.
Before you start #
We are assuming that:
- You have warped you loom, threaded your heddles and sleyed your reed.
- The warp has consistent tension across all ends.
- The warp threads pass through the middle of the reed.
- You have pulled the jack pins.
- The treadles hang at a convenient height above the floor and can be pushed down as far as the jacks allow.
- The upper and lower lamms all sit roughly horizontal with the loom at rest.
If any of these don’t apply, review your tie-up and warp before proceeding.
Hopefully you are using Texsolv cord. When we talk about lengthening or shortening a cord, we mean moving the peg that secures it by just one buttonhole at a time. Remember that the bottom of the shed is formed by the upper lamms pulling down on their shafts, and the top of the shed is formed by the lower lamms pulling on their respective jacks and so lifting their shafts.
Treadle #
Push down on your first treadle – or get a willing assistant to do so for you. Now look down the tunnel that your open shed forms and make a note of which shaft has warp threads that are too high or too low and so don’t align with the others. If the treadle hits the floor, make a note of this too. Release the treadle and repeat this process with all of the treadles.
Analyse #
If any of the treadles hit the floor, you will need to shorten some cords.
Otherwise, it is better to lengthen cords on one or more shafts to create the widest possible shed.
Your notes should look something like this:
Treadle 1. Bottom of shed, shaft 1 too high. Top of shed, shafts 2 and 4 too low.
Treadle 2. Bottom of shed, shaft 3 too high. Top of shed, shaft 2 too low.etc.
Now you can start to correct the lengths of the upper and lower lamm cords. Taking each shaft in turn and proceed as follows.
Bottom of shed #
Warp threads were too high: shorten the upper lamm cord for the shaft.
Warp threads were too low: lengthen the upper lamm cord for the shaft.
Top of shed #
Warp threads were too high: lengthen the lower lamm cord for the shaft.
Warp threads were too low: shorten the lower lamm cord for the shaft.
Repeat #
Push down on each treadle again, and re-check the shed. Hopefully everything is perfect. If not, note down the problems, and you may need to lengthen or shorten cords again until you get the top and bottom of the shed consistent.
