The required force shall be applied by a screw mechanism for compressing a calibrated spring the proper amount. The spring shall be of properly heat-treated spring steel with ends ground and perpendicular to the longitudinal axis of the spring.
The requiredforce shall be applied by a screw mechanism for compressinga calibrated spring the proper amount. The spring shall be ofproperly heat-treated spring steel with ends ground and perpendicularto the longitudinal axis of the spring.