The jig used to build a Flemish string performs a very simple task. The jig is constructed in such a manner that the individual strands of B50 are "feathered" in length - ie., they are not exactly the same length. It is possible to craft a Flemish string without a jig such as this. But, if you're going to make more than one Flemish string - it's worth the wood, nails, and few minutes to construct the jig. Even if you are only going to make one string (yeah, right!) - it will most likely take less time to build the jig, than to do the math to figure out what length the strands should be, measure and cut them. I didn't do the math - I built the jig. It's not the math that's the problem - it's the tedious job of measuring out the 14 strands of B50 I was avoiding ....
The figure below shows the top view of the jig. A
2x4, 2x3, 2x2 or piece of firing strip can be used. The board needs to be a
couple inches longer than ½ the length of the longest string you plan to
make. Hence if you have a 66" longbow, with a (actual) string length of
63" you'll need a board about 33½" long.
Draw a center line through down the board. Start the nails about 1" from the end of the board, each pair of nails are spaced ½" from their neighboring pair. The number of pairs (columns) of nails required depends on how heavy a bow you're building the string for. Basically - for a 14 strand string - you need 7 pairs of nails, for a 16 you'll need 8 (get it - ½ the number of strands in the string=pairs of nails). To determine how many strands based on bow weight, consult the B50 Strand Requirement Table. The lone nail show to the right end of the jig in the figure gets located based on how long of a string you are building. The String Length Formula indicates this dimension as the "Jig Post-to-Post Length". This length is measured from the left-most pair of nails. After I locate the right-most nail, I note the measurement on the jig for future reference. You could measure and mark-off a scale/ruler the whole length of the jig to same time on future strings. You could also drive holes and substitute a dowel instead of the nail - but hey, the objective is to make the string and get out shooting with it, right?
Anyway - I think between this brief write-up and the diagram, you should be able to construct a serviceable jig. If you've got any questions or its not self-explanatory, email me and give me hell.
FIGURE 1 - Top View of the JIG
