I keep a stock of replacement diaphragms, but I have to admit that very, very few people need them. In fact, I've never sold any at all. Crossing them over 3rd order at 1600 with 10dB attenuators - No way to blow 'em. A person would need a few thousand watts of full-power screaming siren sound or something, and even that would take out the protection bulb first.

Anyway, I'll check the screw sizes later tonight. I can't do it right now, but I'll check for you and let you know.