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Tapping Guide

Home Up Tapping Terminology Tapping Guide Metric Taps BA Taps Metric Dies Drill Bits UNC Taps BA Dies Glow Plug Taps UNF Taps UNC & UNF Dies BSW Taps BSF Taps BSW & BSF Dies Trend Snappy

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Through Hole  

A hole drilled from one side of the material through to the other side.

Blind Hole   A hole drilled into a material from one side without penetrating the opposite side.
Tap hole diameter  

This is the correct diameter that should be drilled prior to tapping the female thread

Taper Tap

This is the initial tap used to start the tapping process for a female thread. They have a long lead in of 7 to 10 threads.  Also often referred to as '1st Tap'.

Second Tap

As the name suggests, this is used after the taper tap to produce the full thread in 'through holes' or 'blind' holes where the thread does not need to go close to the bottom of the hole. Sometimes referred to as 'intermediate taps'

Bottom Tap

Used where the thread is required to extend near to the bottom of a blind hole. Often termed a 'plug' tap in the UK.

Split Dies Dies are used to cut male threads - i.e. as on a screw. These most common form are split dies which enable some adjustment of the diameter for increased accuracy and to compensate when the die eventually wears.
Tap Wrench - 'Tee handle' type

A tool for holding the tap during the hand tapping process. The type shown has a chuck that is tightened by hand to grip the tap. this style is particularly suited for the smaller tap sizes

Tap Wrench An alternative to the tee handled wrench above, this is the more traditional style that is needed for larger size taps. Should be used with great care for very small taps due to the long leverage length
Die Holder

A tool for holding the die during the hand tapping process


 This page was last modified on : June 28, 2023

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