After the profile draft has been threaded, how is the profile tie-up interpreted? The block tie-up for 4-shaft overshot is unique. There can be only one block per row and one block per column, and the blocks have to follow in an odd-even alternation. For instance, if there is a black square in row 1, column 1, this is called Block 1. It can be followed by either Block 2 or Block 4. If there is a black square in row 2, column 2, this is Block 2, which can be followed by Block 1 or Block 3. Likewise, if there is a black square in row 3, column 3, this is Block 3, which can be followed by Block 2 or Block 4. Finally, if there is a black square in row 4, column 4, this is Block 4, which can be followed by Block 3 or Block 1. There are really only eight "legal" tie-ups for traditional four-block overshot. The tie-ups include:

A black square in the block tie-up indicates which block in the woven fabric will be covered by the heavier pattern weft. If Block 1 is indicated, then all the warp ends in Block 1 will remain down so that the weft can float over them. Since Block 1 is threaded on shafts 1 and 2, those shafts remain inactive, or in the down position, while shafts 3 and 4 raise up. If Block 2 is colored in black all the threads on shafts 2 and 3 remain down while shafts 4 and 1 are raised. If Block 3 is intended for the pattern weft float, then shafts 3 and 4 remain down and shafts 1 and 2 are lifted. Finally, if Block 4 is the pattern block, shafts 4 and 1 stay down, while shafts 2 and 3 are lifted.

The tie-up for a profile block arrangement of 1.2.3.4 becomes 34, 41, 12, 23. These are the lifts for the pattern floats. What about the lifts for the plain weave fabric? The lifts for plain weave (where every other thread is up and every other thread is down) are created by raising shafts 1 and 3 and raising hafts 2 and 4. In a thread-by-thread drawdown, usually only pattern float wefts are indicated. The plain weave picks are not drawn in.

The profile treadling plan indicates the sequence in which the threaded blocks will be covered by the pattern weft. There are usually as many pattern picks of weft as there are ends in the threading block. So a single treadling block indicates a lot of information. Not only does it imply three plain weave picks, but it also implies three pattern wefts. If there is a single black square in the profile treadling sequence under Block 1 in the tie-up, six wefts are thrown.

raise shafts 1 and 3 - plain weave pick
raise shafts 3 and 4 - pattern weft floats over ends in Block 1 threaded on shafts 1 and 2
raise shafts 2 and 4 - plain weave pick
raise shafts 3 and 4 - pattern weft floats over ends in Block 1 threaded on shafts 1 and 2
raise shafts 1 and 3 - plain weave pick
raise shafts 3 and 4 - pattern weft floats over ends in Block 1 threaded on shafts 1 and 2

In order to get these six picks to pack into the woven cloth so the block will "square up" or weave to square, requires the correct size ratio between warp and weft, and the correct loftiness or softness of the float weft. If the float weft is too thick or too stiff, it will not pack in as well. Sometimes, reducing the warp sett, so there are fewer ends per inch, can alleviate this problem with a float weft. Using a smaller diameter weft for the plain weave cloth may also correct the packing problems. Sampling is crucial when weaving overshot.

For every square in a treadling plan, weave three plain weave or tabby picks alternating with three float picks. For every double width square in a treadling plan, weave seven tabby picks alternating with seven pattern wefts. For every triple width square in a treadling plan, weave eleven tabby picks alternating with eleven pattern wefts. The number of pattern picks can be reduced or increased to make each block square up.

Most of the blocks in a treadling plan will weave with an odd number of pattern wefts. The one exception is the "turning block" in the treadling plan. Where a block reverses its path in the profile treadling plan to create a mirror image of the draft, this is known as the turning block. When weaving the turning block, use an even number of pattern wefts so that the plain weave picks will be in the same shed at the beginning and ending picks of each turning block. For instance, if the turning block is a single block in width, implying three warp ends in the thread by threading draft, weave four pattern picks. Start with the plain weave pick followed by the pattern pick.

Shafts 1 and 3 - plain weave a
Shafts 3 and 4 - pattern pick 1 - Shafts 2 and 4 - plain weave b
Shafts 3 and 4 - pattern pick 2 - Shafts 1 and 3 - plain weave a
Shafts 3 and 4 - pattern pick 3 - Shafts 2 and 4 - plain weave b
Shafts 3 and 4 - pattern pick 4
Shafts 1 and 3 - plain weave a

If the turning block in the profile threading draft is a single unit threaded on three warp ends, weave four pattern picks at the turning block in the treadling plan. If the turning block in the profile threading draft is double width threaded on seven warp ends, weave eight pattern picks at the turning block in the treadling plan. If the turning block in the profile threading draft is triple width threaded on eleven warp ends, weave twelve pattern picks. This assures that the tabby preceding and following the pattern picks of a turning block will be in the same sheds.

Convert Draft II into a threading draft with a tie-up and treadling plan.

The threading draft and tie-ups have already been discussed on the previous page. Where are the turning blocks in the treadling plan? There are five turning blocks. The first is a double width sized at Block 4. The second, third, and fourth turning blocks are on blocks 1 and 4. Each will contain four pattern picks. The fifth turning block is double width at Block 4 and will contain eight pattern picks. The full drawdown is shown below. The red arrow in the threading draft indicates where a pair of warp ends has been added. The red lines in the treadling plan indicate the even number of picks in the turning blocks.

Only the pattern picks are shown in the drawdown. The plain weave picks are not shown. Usually begin weaving overshot by lifting a plain weave shed on shafts 1 and 3 followed by a pattern pick covering warp ends in Block 1 by raising shafts 3 and 4.