I'm trying to work through the "Introducting Autodesk Maya" tutorial book (the chapter where you animate a locomotive using bones and an IK chain), and I'm getting stuck and very frustrated. 
Basically, I cannot get the steam-pump arms of the locomotive to animate properly; one end is supposed to stay stuck in place (at the pump assembly) and the other end is supposed to move with the wheel when it animates (y'know, like a regular locomotive). Problem is, whenever I create the joints for the pump-arms, the arms want to go flying up in space whenever I move the wheels, instead of one end staying stuck to the pump. I've tried creating IK handles at either end, and setting keyframes to make them "stick" in place, but to no avail; they still go flying in the air. Can anyone help me get this thing rigged correctly? I'm enclosing screenshots of my Outliner, perspective view, and a reference to the book (page 440). Here's the procedure I'm following:1. Load the locomotive model.
2. Select the pump-arm in perspective view.
3. Create a joint where the arm meets the wheel (root); create another where it meets the pump; group the pump-arm under the first joint and the first joint under the wheel.
4. Create an IK handle at the pump-end.
5. Create a transform key at frame 1 for the IK Handle
5. Rotate the wheel — pump arm goes flying up still!!
Can anyone help me out, here?
I understand what the piston tutorial is getting at, but the book wants me to solve the problem using IK and joints. I've made SOME progress since I made this post, though: Now, the arm's front end stays "glued" to the pump part, like it should, and the arms move with the wheels, but their movement is way off . . . if I turn the center wheel (the parent of the joints), the arms move correctly, but they move way outside the range they should be moving in. I tried using Constraints on them, but Maya tells me that the "list of targets" is empty and errors out. What do I need to do differently here? I've attached a couple of screenshots to show how I've got it working thus far . . . see how when the wheel is at zero degrees rotation, the armature assembly is where it is supposed to be. But, when i rotate the wheel 100 degrees, the arm flies way up above the wheel, and then back around behind it, etc., moving to the exact same degree as the wheel is, but needing to be "confined" somehow to just moving up and down, in and out on the wheels. Any ideas?
