I'm just wondering, but... Why do Gillette adjustables have the quarter turn feature when all their other TTOs do not?
I take it your are referring to the locking mechanism. Quarter turn after tightened. Should be present on Gillette adjustable, if not usually means internal spring gunked up. Oddly, I have the feature on my new red tips and they're non adjustable TTO's.
That quarter turn is the spring in the knob compressing. That spring is part of the adjustables' mechanism and isn't present on a regular TTO.
the 1/4 turn function is essentially the compression of the tto rod that compresses the blade support into the blade and the blade into the silo doors.
however at the same time, Gillette was the first company to actually REALIZE that an adjustable razor needed a blade support.