Can anybody please tell me how to bend to wire for an offset Tortoise switch machine? I have three turnout near the edge of my layout and I have to use the offset fulcrums on the tortoise. I fiddled with it all night with no success. Except I did manage to mangle the spring wire so bad it is now useless Any advice would be welcomed. Eric
Whenever I have an offset for Tortoises, I still use the center pivot. I simply bend the wire at a 90 degree angle towards the points above the pivot and then bend it back vertical at the spot you want it. I also use brass tubing around the wire to strengthen it a bit when I have to do this. Make sure you put some tubing on the horizontal before you make the second bend, or you'll never get it on!
Sorry about the late entry here. I only found I had the same problem in the last few days and had an interesting time. The Tortoise instructions say to request an Application Note for this, but with them apparently not being web-enabled, and not wishing to write air-mail to Circuitron and wait to get it, I decided to try and sort it myself. First I did what looked obvious, but though it drove the points OK it had the nasty side effect of pushing the drive-wire about 1/4" further up through the baseboard in one direction. As I'm using the centre hole in the tie-bar of the switch this has a somewhat terminal effect on the passage of trains . (In the particular situation I have, I might actually have been able to use an end hole in the tiebar and avoided the offset altogether .... if I'd seen this problem coming earlier!) I've now solved it by using a longer drive-wire with more bends in it which the sketch below illustrates. The problem to solve is that when the Tortoise operating arm moves from B to A it pushes the rod in the direction of the arrow. Look at the diagram and you can see why. To control this I have put a step in the drive-wire at the fulcrum so it cannot go any further through the hole. I extended the wire into the loop you see here to give it some extra 'spring' in the vertical direction. This springiness is then used to keep the step in the wire in contact with the fulcrum, and therefore give a constant protrusion of drive-wire from there and through the tiebar. Once the the drive-wire is bent near to final shape it is tweaked as follows. The last bend of the wire (near B in the diagram) is altered so that when the actuator arm is at B the force in the direction of the arrow is minimal. When the arm moves to A the force will increase, but shouldn't be so much as to start distorting the operation. When the force is good I centre the arm and, if needed, bend the drive-wire near the pivot point to get the points near mid travel. Finally trim off any excess wire protruding through the tie bar. And yes, my loop does have that 'threepenny bit' look .
The only Tortise motor I ever saw was at a train show, used, for sale, and had the wire "arm" on the shaft. I was afraid of the motor burning up in a stalled state, so I didn't buy it. The short end of the wire was clamped in the motor shaft only sticking out the bottom about .015" at the most. (I could "just" feel it with my finger.) Sitting against the top of the motor shaft was a coil wound in the wire about 3/8 or 1/2" in diameter, with the long leg of the wire sticking straight up vertically centered between "A" and "B". There was a reverse bend on the short end that aligned it with the center of the coil, and another reverse bend on the long leg, so it would also be on center line from the motor shaft, through center of the coil, and along the long end. (As if a long straight wire would be, see?) It appeared to be so the motor shaft could rotate all the way from "A" to "B" and the coil would wind up or wind down to provide tension yet allow the end of the wire to only go either way as far as the rails would allow. I do not remember the size of the wire, but I think it may have been around .020" to .050" diameter and looked like music wire. I asked how he made it, and he said he "C" clamped the wire between two small sticks with one end of the wire clamped to the shaft under the head of a small screw. As he rotated the 3/8" diameter shaft by hand in his drill press, the wire wrapped around the shaft tight forming the coil. He must have laid each coil next to the previous coil as he went. He had several coils, maybe four or more, I do not remember. He said when he got enough, he let the wire un-coil a bit by removing the screw on the side of the shaft, and took off the clamp on the two sticks. Then he used needle nose pliers to hold the coil, and flat nose pliers to make the reverse bends so they would align with the center of the coil, and cut the wire to length on each end as he needed. Finished, it would look like you had drawn the letter "O", then drawn a line through the middle of the "O", then cut out the wire inside the "O". I have never tried it, but he had used it, so it must have worked. This might be easier to "tune" than the one shown above?
Eric, I've also installed a number of offset tortoises and used the center guide bar. In most cases I needed to get a heavier wire (piano wire) and bent the wire after going thru the guide bar. In some cases I bent the wire more than 90 degrees to compensate for the wire tending to move upward. I'm being vague because I'm away from my layout for awhile, but each installation was a little different and in all cases I was using Peco turnouts which are easy to switch. Take care, Jim
