Putting together exercise equipment? I put together an elliptical contraption. I missed a step and...

I put together an elliptical contraption. I missed a step and the bar surrounded by the middle of the machine moves side by side when i use it. I tried to give somebody a lift the bolt off of the tablet, but it won't come off. The bolt will turn close to it is coming off, but it won't come past its sell-by date. How can i get it to come past its sell-by date?