This comes from page 44 in my Book #1, Winding a Warp & using a Paddle.
Here is how to use a counting string to keep count of how many threads you’ve measured. I like to use it to mark off every 5 round trips on the warping board–AT THE RADDLE CROSS END OF THE WARP.
The best method I’ve seen for counting is this special crocheted chain. See Figure-76. Take a long string (about three feet), fold it in half and slip the two tails through the
loop at the fold around your first five raddle groups.
This makes a lark’s head knot over these five groups.
See Figure 75. With the tails of the lark’s head you will begin to crochet around the bundles as you make them.
Measure out your next five groups. Fold the tails between the
first bundle and the new one, making a loop. Then put your
right thumb and forefinger into the loop, while holding the
tails with your left hand.
Encircle the new bundle with a “crochet” by using your finger and thumb to draw up another loop from the tails. Holding onto the tail, pull on the loop to snug it up around the bundle. Leave that loop and the tails dangling (don’t pull the tails through the loop, as you’ll be tempted to do).
The lark’s head knot is the foundation. From now on, you’ll crochet-chain using
your fingers like this. Measure the next five groups. With thumb and forefinger, reach through the old loop, drawing up a new one from the dangling tails, and tighten to secure the new bundle. After each crochet, both the loop and the
tails should hang freely, ready for the next bundle.
To end the counting string chain, at the last
bundle, pull the tails completely through the
loop so that only the tails are hanging freely.