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Tap Terminology

 


The hand taps supplied by Grove Components are straight flute general purpose tools which can be used for either machine or hand tapping. The three types of tap (Taper, Second and Bottom) and their applications are described below:

 

TAPER TAPS have a chamfer (lead) of 7-10 threads at 5 degrees per side. The taper lead distributes the cutting force over a large area, and the taper shape helps the thread to start. They can therefore be used to start a thread prior to use of second or bottom leads, or for through holes.

 

SECOND TAPS have a lead of 3-5 threads at 8 degrees per side. They are the most popular and can be used for through holes, or blind holes where the thread does not need to go right to the bottom.

 

BOTTOM TAPS have a lead of 1–2 threads, the angle of the lead being around 18 degrees per side. They are used to produce threads close to the bottom of blind holes.