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c.) Tap
Insert square end of tap into tap wrench and tighten handle to secure in place. Lubricate cutting edges.
Great care must be used when starting the tap into hole. Tap must be held square (90˚) to work piece.
Begin by turning tap slowly clockwise with light downward pressure. As the tap is turned, it will bite into
the material, pulling itself forward into hole. Once the tap begins to cut, chips of material are formed
between the flutes of tap. These chips must be broken off to relieve pressure against the tap.
This is accomplished by momentarily reversing tap direction every 1/4 to 1/2 revolution, depending on the
resistance encountered. Continue this alternating pattern of forward and reverse rotation until tap passes
through work piece or to desired depth. Blind hole (does not pass completely through work piece):
The starter threads (first 3 to 5 chamfered threads) on these plug taps do not cut full threads.
Therefore, when drilling a blind hole, it is necessary to make the hole deep enough to allow extra room for
falling chips and the starter thread to fully clear threaded section.
USING DIES
Dies are used to cut threads on the outside of a rod, creating a threaded
bolt. The diameter of the rod is of great importance. It cannot be larger
diameter than die (thread size) and preferably the rod would be .005
- .010" undersized. Oversized rod may damage the die and will make
turning the die very difficult or cause damage. Slightly undersized stock
is easier to thread and can make more uniform threads.
a.) Chamfer
To enable die to start easy and straight, bevel the end of rod.
The chamfer can be created by filing or grinding by hand or
by power tool.
25 PIECE SAE
LARGE TAP & DIE SET
TAP WRENCH
90°
Page 3
25STDS
To properly cut external
threads you will need:
• Die of correct size
• Die stock
• Rod of correct diameter
• Lubricating (cutting) oil
1911358-14
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