Abstract: The invention provides an improved standardized blank adapted for making taps for making tapped holes and an improved positive lock tap holder. A standardized tap blank is provided which is standardized as to diameter, overall length, and shank length. Such a blank is adapted to manufacture a wide range of taps of varying thread sizes, both U.S. and British standards, and metric standard. For broadening the range of capacities that the blanks are adapted for, a set is provided including two additional standardized blanks, standardized as to a different diameter shank length and overall length. Each standardized blank is provided with a square end, standardized as to the square sides and overall length. The standardized tap blanks are further provided with an annular groove to for holding balls.

Abstract: A screw thread cutting apparatus (tapping attachment) which is provided with a clutching apparatus within the attachment, having the capability of de-clutching the drive from the driver in the event of excessive torque. The clutching apparatus involves a clutching member or members carried by the driver and a clutching member or members carried by the driven part, and a displaceable clutching member which can produce a clutching or de-clutching action between the other members. The clutching apparatus can be built into an adapter for holding a tap provided with quick change capability. The clutching apparatus can also be built directly into the driver.

Abstract: The invention is an apparatus for producing clutching and de-clutching particularly adaptable for use in a tapping attachment for threading holes. The clutching apparatus includes clutching members driven by the driver or driving machine and clutching members carried by the driven part. An intermediate member is provided which provides for clutching engagement and de-clutching between the members on the driving part and the members on the driven part. The clutching apparatus has the capability of producing de-clutching in response to excessive torque applied to the apparatus, and also, it has the capability of producing de-clutching in response to the tap having reached a predetermined depth and the hole being tapped. The apparatus can be built into a tapping attachment or into a tap holding adapter having the capability of quick change release, and also, the mechanism can be built directly into the driving apparatus.