I came up with a hybrid. It uses the belts for the drive side, and the fishing line on the idler side. I also am using a zip-tie tensioner.
Doing things this way, we only need belts as long as our smooth rods.
It's not running yet, as I am waiting on my pololus. But it looks like it should work out.
Delta RepRap using both belts and Spectra fishing line
I have this new RepRap 3D printer that I am putting together. It is based on the Rostock style printer. It came to me half assembled, sans electronics. It had been running, but got pirated for part…