Insert bit for use with a powered screwdriver

摘要

PCT No. PCT/US94/00441 Sec. 371 Date Nov. 27, 1996 Sec. 102(e) Date Nov. 27, 1996 PCT Filed Jan. 26, 1994The present invention relates to the field of insert bits (10) for use with powered screwdrivers. The formed bits (10) may be treated to have a desired microstructure by either an austempering process or by the three step heating, quenching, tempering process. The bits (10) may also be electro-polished. Austempering provides for improved function and increased fatigue life and electro-polishing provides for improved function and increased fatigue life and torque capacity. The bits (10) and may have reduced diameter midportions (30), particularly for use with impact drivers.