The pressed/stamped pressure plates used from late 1926 to mid-1970s always were a bit ‘borderline’ in terms of stiffness and rigidity, especially when used with the stronger clutch springs used on TT Reps, Sprint Specials, etc.. The ‘works’ TT bikes that I have restored have a much stronger (steel) plate that is a machined-from-solid item, not a pressed/stamped effort.
