054 Corner Pulley
Without a doubt, this was the most difficult model to build in this series -- so far. Nothing held together. The photo below I took after positioning and repositioning the components for over an hour.
If you look carefully at the illustration, you can see what some of the problems are. The string wraps around a dowel. But that dowel isn't really secured to anything. As illustrated, it appears to hang over the edge of the base, with one small dowel securing it. That didn't work at all -- even though I was using wire rather than rubber bands or string.
I compromised by placing the dowel through the base hole in the corner, and further securing it with t a second dowel through the middle slot of the base.
The crankcase was also a problem. The posts supporting it simply couldn't hold it once any tension was applied. And even though the only tension was a bent wire, it still couldn't handle it. So I had to continually pull the crankcase back up into position. And that pulled the corner dowel to the left, and that caused the end pulley to come apart.
It's not perfect, but this is as good as it's going to get.