[JesseK]

Just got done with a 15 hour robot day...man we got so much done today...

We inlined the sprocket so the chain coming off both sides is exactly vertical. We then made a hardware store run and bought varying full-threaded eyebolts, made a new mount, and tensioned the crap outta both sides of the chain. It's still holding and hasn't slipped since we first did it. We DO have an interesting video with pretty cool real-life sound effects of what happens when the chain pops off the sprocket when the lift is at full height though...that was fun...

Thank God, that one part alone wasted us 36 build session hours! It's our first real elevator and man I'm glad it's over. After that every other piece only took an hour or two to integrate onto the lift and bot and it looks like we'll make Monday night.

edit: When at full height, the chain was bowing the elevator backwards, if you can picture that. Then, on the way down, the chain would pop off. To fix it, we had to fine tune our mounts and move the sprocket, pulley at the top, and all tensioners to about 1/8" or less from the gearbox on the output shaft or corresponding mounting surfaces. Wish this was in an elevator FAQ somewhere.