I did a certain crossing eye mechanism a little more than a decade ago, and experimented with this style for 2 reasons. One, just to verify I could do it (its a little fancier than some and tested my soldering skills), and two, to verify its usefulness in a figure. Here’s a few pictures:
Basically it’s a telescoping mechanism, where a brass rod rides inside of a brass tube, and has a return spring. There are also 2 brass rods soldered to the tube and project out the back of the mechanism to connect to an ‘L’ shaped eye rod control (see example here).
Cord is tied around the rods on the back of the eyes, and go through ‘screw eyes’ in the sides of the head. When the cords are pulled, the mechanism telescopes like in the 3rd photo above, and the eyes cross. When released, the spring pulls everything back into the normal position, and the eye are no longer crossed.
Does it work well?. Yes, flawlessly. Is it practical or worth the trouble? Debatable! Often times simpler is better. The photos below show a much simpler method of achieving the same thing. It is based on one of the synchro/self-center mechanisms shown in my book, that uses two springs off the back of the eyes:
To that basic arrangement, screw eyes are added to the eyeballs, and cords are attached that will pull from either side through screw eyes in the sides on the inside of the head. See photos below:
When the cords are pulled, the springs allow the eyes to turn inward thus crossing the eyes. When the tension on the cords are released, the springs pull the eyes back into the normal position (like in the photo above). See photo below of the eyes being crossed:
The mechanism is very simple to make, takes very little skill to install, and works great. It self-centers the eyes, provides the synchronization of the eyes and allows them to be easily crossed. Back in the late 1990’s, when I met with figure maker Rick Price to discuss different mechanisms, this was one that we talked about.
There were certain mechanisms that Rick and I discussed at some length, but were held back at the time from being published in my book for various reasons (sometimes out of respect for a certain figure maker). Its been so long now, I can’t remember why this one did not get included.
Truth of the matter is, I’ve had many discussions with those learning figure making over the past decade or so, and have shared this simple method with them, and I know they have shared it with others as well. There’s a number of figure makers currently using this method. It was actually in use for some time prior to when I first learned about it.
In any case, it’s a good example of the old axiom that, ‘sometimes simpler is better’!