Greenfield Threading 355803 Straight Flute Hand Tap #3-56

Three-piece tap kit for #3-56 threads

This kit contains three straight-flute hand taps designed to cut #3-56 UNF threads in a single operation. The set includes taper, plug and bottoming taps so the user can start, continue and finish the thread without changing tools. It is intended for mechanics and maintenance technicians who need to create or repair fine-pitch threads in metal workpieces.

UNF standard limits thread pitch and form

The taps follow the UNF thread standard with a 2B class of fit and H2 thread limit, which fixes the allowable pitch diameter tolerance for general-purpose fastening. A 75 percent thread depth is produced when the recommended #46 drill size is used, and the right-hand thread direction is the only orientation these taps support. The fixed geometry means the kit cannot cut metric, coarse or left-hand threads.

High-speed steel with TiN coating determines tool

Each tap is made from high-speed steel and coated with titanium nitride to resist wear during hand threading of ferrous and non-ferrous metals. The coating extends edge life compared with uncoated HSS, but the material still requires cutting fluid and proper alignment to avoid breakage. Buyers who need taps for high-volume CNC tapping or for hardened steels above the coating's capability should select a different tool.