For the last one hundred years or so most North American bit makers have been using these designs without realizing their historical significance. Today both English and Western bits work by applying pressure. We apply pressure until the horse drops his head, relaxing his jaw and yielding to this pressure. Different horses respond and accept pressure from different areas. That is why we have so many different bits.
Horses also respond to different pressure points better at different stages in their training.
It is up to the person riding or training the horse to find out which particular pressure point or points he will respond to most favourably. Meaning which pressure points he not only responds the lightest from but carries himself in a steady, relaxed manner. My bits are known for their balance. By balance I mean if the horse raises his head too high, the bit will come in contact with one or more of these pressure points, encouraging him to drop it to a more comfortable zone. I build my Quarter Horse bits so that this comfort zone is obtained when they lower their heads to the vertical.