A clamp bolt assembly for a clamping mechanism, particularly for an adjustable steering column for a vehicle, includes a substantially cylindrical bolt or rod with one end threaded to receive a lock nut and with its other end having a reduced-diameter portion to form a shoulder against which a pack of disc springs can be held in place by a nut preened onto the end of the rod. According to one preferred implementation, a diffusion region is formed in semiconductive material. A sense amplifier is electrically connected to the current comparator and a reference current generator.