Originally Posted by JohnDThompson

It's adjustable to a certain extent by how tight you wind the spring before you lock it in place with the end plate. That's almost a three-hand job, although I have accomplished it by clamping an Allen wrench in a vise, inserting the pivot shaft onto the Allen wrench, and rotating the body until the spring tension is sufficient and the flats on the pivot shaft end line up with where the end plate needs them to be. Then, holding everything in place with your two hands, you reach over with your third hand for the end plate, put it onto the pivot shaft, and lightly tap it lightly in place, taking care not to knock the Allen wrench out of the vise or the bolt off of the Allen wrench.



Yeah, that's going to be a problem. Without the flats on the end of the pivot shaft, there's nothing to retain the spring tension. If there's barely enough flat left to hold it in place long enough to get it mounted on the dropout, the mounting bolt (inserted from the back) may be able to hold things together, but that's an ugly kludge and likely to fail at an inopportune moment. Better to acquire or fabricate a replacement pivot shaft with intact flats. Many of those pieces are interchangeable among the various Simplex models, so a derelict derailleur might supply a decent replacement.