This has been a reoccurring thing for a while and progressively getting more annoying, so I'm working on getting it taken care of.

When I try to start the car, I can hear the relay click and I can also hear the starter clank, but the starter doesn't spin, just hammers forward. I have my battery in the trunk and I put a new battery in and it didn't get better. I also took the starter off and tested it and it worked fine, but I replaced the solenoid anyway with one that I knew was working better. When I did that, I think it made the problem a little bit worse. That leads me to believe I might have fiddled with something while I was in there that could have made it worse. I'm gonna double check my grounds but I'm wondering about the starter. The power coming from the battery right onto the starter helps it spin and the wire coming from the relay pushes the gear forward to mesh with the flywheel. Correct? Or do I have it backwards? Anyone have a similar problem where the starter did everything but spin?

Well you kind of have the right idea on how it works. The small wire that goes to the starter solenoid comes from the ignition switch and supplies voltage to the starter solenoid when the switch is turned to the Start position. The solenoid then pushes the bendix gear into position to turn the flywheel. The solenoid also then connects the main battery lead to the starter motor windings when it moves foward through some heavy duty copper contacts and a bar. There is a lot of current needed to run the motor and the load on it. The motor then turns the engine around.

Since you hear the solenoid working but not the starter motor you need to check a couple of things. First make sure that the solenoid contacts are making good coonection. This may be hard to do since they are consealed inside the solenoid. Another problem could be the motor windings are open so the motor won't turn. Getting a rebuilt starter may be your best option. One other thing that could be happening is the engine may be locked up. You should check that too before replacing the starter.