I never use the very thin plates that have been available on either pre or post war singles. As has been said earlier there should be a thick (stepped) plate at the back then alternate bonded and plain steel plates. Overtightening should not cause them to become concave but excessive heat through slipping is the cause of this which is more likely to happen with the very thin plates. Notches in the clutch hub and in the drum certainly won't help. Cheaper bonded plates do tend to stick much worse than Surflex plates. Surflex are more expensive but are well it. I have found that the later type of solid drum is not quite as deep as the old slotted type and consequently you sometimes cannot get the last friction plate in. I have not measured the solid type of drum from the VOC Spares Co so they may not suffer with this problem. If put together with unworn components you shouldn't have any problems. Both my Series A's and my Series C go into gear without a sound.
Brian Werrett (joint Series A organizer with Peter Barker)
