Calibration of 8" floppy drive?

Seems like eons since I learned to align PerSci 299B's with Dysan alignment disks and 'cat's eyes' on a 'scope :) I echo the other sentiments here - do NOT undo or unscrew anything relating to head positions especially involving allen (hex) screws unless you have a 'scope, an alignment disk, a very good quality set of hex screwdrivers (keys will normally NOT suffice) and a modicum of experience. Granted, lead screw single-headers are a little easier to do than voice-coil double-headers but if you don't have to get into it then don't - explore all other options first. I'm afraid my TM-848's are double headers so the top head provides the pressure but back when the drives were single headed felt pads did the job of the second head. The tension was provided by the spring, the pad just prevented scoring. I do NOT speak from experience BUT if I had to use anything the kind of small felt pads you can get from hardware stores (e.g. B&Q in the UK) seem remarkably similar in composition and would be worth a try especially if you have one original to compare. Cut to shape, most are self-adhesive too - bonus. HTH James