For instance, one of the selling points of my saddle was that I knew it had an adjustable leaping head. Just how one was to be adjusted still puzzled me even after the saddle arrived. Nothing seems obviously adjustable. I soon found out that just twisting a few things wasn't going to majikally adjust anything. Quite a bit of reading, and some emails later, and I was ready to experiment on the old gal.
See the little silver thumb screw in the middle of the leaping head? This holds the leather cover onto the frame. Remove it, and the leather slides off. Of course, the screw was in there pretty good, and at first I was hesitant to try to remove it. Finally, I covered it with a cloth and gave it a twist with a pair of pliers. After the first quarter turn, it unscrewed very willingly.
I'm sure your thumbscrew isn't something you want to go missing. My husband seems to think he can find me a back up supply of a similar creature for just in case, if he does, I'll let you know.
Removing the screw reveals the hole in the leather and frame. Having the screw in that hole simply keeps the leather head from loosening and sliding off on it's own.
The leather slides easily off the curve of the iron "tree".
This leaves you with a strap of iron, which can be unscrewed from the tree. With the leather on, the head will only swivel back and forth. The leather head interferes with unscrewing it.
Leaping head from side with leather covering removed.
You can see that there are two holes to place the head in. The one towards the back is holding a blank plug that can be removed and placed in whichever hole is unused.
Now, besides the two positions in the tree, the iron itself can be reshaped. You can see from the marks that this one has been shaped more than once in it's history.
As for fitting my thigh, the way the leaping head was, the tip was hitting me on the outer edge of my thigh. The curve itself was fine, but it was too close to the saddle. I found if I backed the head out one full turn, the extra eighth of an inch that the base moved away from the saddle allowed my thigh to fit the head perfectly. Once again, I have all the right curves, they're just a bit too far apart. It would have been great if that was all it took. But, leaving the head backed out one turn prevents it from snugging into the tree. It would just turn back until the leather heads interfered. There was no actual stability. Besides being unsafe, the wobble of the bolt in the hole would wear on the already antique threads.
The leaping head is designed on a left handed screw. What this does is when the rider raises out of the saddle (for instance in the jumping position) the screw turns left with the thigh, then hits it's snug point and provides a firm block to the thigh. My husband fantasized about finding a 5/8" left handed lock nut (not very likely) to stabilize the head when it was backed out of the tree one turn, but this would have prevented the head from turning at all, and you need some swivel in the head to move with your thigh.
So, in the end he took it out to the shop, put it in the vise (padded with cloth) and just unbent the curve a touch. I sat on the saddle in the middle of the kitchen waiting for him to get just the right bend. It only took two tries to straighten it just the eighth inch or so I needed. He didn't even need to heat it, and in fact, preferred not to because he knew it would ruin the chroming. The leather head now goes on a bit reluctantly since it has conformed to the curve it has been in for the past 85+ years. Opening the curve was pretty simple. Closing the curve in a smooth arch would be a bit trickier, and would probably best be done by a farrier who could heat the iron and who would have the tools to create a nice curve.