In case anyone still happens to be confused about this item...
You need the key item "Fletching," which is purchased with clothcraft guild points. Once you have the key item, you can use the recipes above to craft more fletchings with one crystal with the help of zephyr thread. Zephyr Thread is useless for crafting purposes without the key item.
This is a similar process to using spindles to craft more thread with one crystal with the key item "Spinning."
Edited, Jul 14th 2007 7:01pm by Moonsong