Drive pulley and end of drum
This shows the metal plate I fitted under the pillow block on the drive end, to reduce the effect of vibration allowing the pillow block to recede into the soft pine.
You can also see the double-sided tape used to attach the sandpaper. One 1/2" strip 3/4 of the way around the drum is ample to hold the paper at each end - none is needed in the middle.