Abstract: A rock drill bit having a shank and a replaceable cutting head, comprising steps of producing a shank having a tip with an outer surface having a given shape, producing a head having a working face at one end and a recess at the other end with a cross-section corresponding in shape to that of said shank tip, and having a size about 0.15% less than that of said shank tip, cooling said shank in a cryogenic gas at ambient pressure to reduce its size, installing said head on said shank tip, and permitting the components to return to ambient temperature, to establish a shrink fit between the head and the shank.

Abstract: An electronic musical instrument includes an emphasis circuit for independently modifying the level of each musically encoded data channel of a selected automatic accompaniment pattern in response to a parameter characterizing key operation, such as key velocity or key aftertouch force. Channel level modification is effected by modifying the MIDI velocity data byte of each channel in accordance with a value selected from a respective emphasis table in response to the current value of the key operating parameter.