[philso]

How are you going to mount the body of the encoder? If the axis of rotation of the encoder is not exactly lined up with the axis of rotation of the object you are measuring, the forces will break the glue joint as the assembly rotates. If exact alignment cannot be guaranteed, it would be best to use some compliant coupling between the encoder shaft and the component being measured.

It might be easier for you to measure the rotation of some other point in your system. If you are using a motor with a gear or sprocket to rotate the assembly, attach your encoder to the shaft of that motor or to the shaft the assembly rotates on.