As of now, the 80T pulley installation page for ERCF (page 29) simply shows to install the 20T pulley inside of it and tighten the 5 screws. Unfortunately, no matter how hard I tried, I failed to ensure the concentricity of the bigger pulley with the smaller one - and, by that, with the D-shaft. Even tightening them by a star pattern, going half thread at a time, makes the assembly offset from the center, with the very first screw that went in pushing the 20T pulley away from the center on the very first half a thread that it went in and the other 4 screws not pushing it back. The drawback in this scenario is not only the belt tension changing, but the pulley rubbing against the motor arm with non-negligible amount of friction in some stages of the D-shaft's rotation.
If there is a good technique to assemble this without it running off-center, it would be best to put it on the documentation page.
As of now, the 80T pulley installation page for ERCF (page 29) simply shows to install the 20T pulley inside of it and tighten the 5 screws. Unfortunately, no matter how hard I tried, I failed to ensure the concentricity of the bigger pulley with the smaller one - and, by that, with the D-shaft. Even tightening them by a star pattern, going half thread at a time, makes the assembly offset from the center, with the very first screw that went in pushing the 20T pulley away from the center on the very first half a thread that it went in and the other 4 screws not pushing it back. The drawback in this scenario is not only the belt tension changing, but the pulley rubbing against the motor arm with non-negligible amount of friction in some stages of the D-shaft's rotation.
If there is a good technique to assemble this without it running off-center, it would be best to put it on the documentation page.