TM 9-243
TYPES AND USES - Continued
STAYBOLT TAPS
Staybolt taps are used in boiler, locomotive, and railroad
shops for tapping holes in the outer and inner plates or
shells of boilers. The staybolt tap has two separate
threaded areas. The first is for cutting threads and the
second is for guiding the tap into another piece of metal
for threading by the cutting threads. The spindle-type
staybolt has an adjustable spindle which changes the
distance between the cutting threads and the guide
threads.
MUD HAND TAPS (WASHOUT TAP)
The mud or washout tap has six flutes, tapers 1-1/4 inch
per foot, and has 12 threads per inch. It is used for
cutting American National or V-form threads in mud plug
drain holes.
DIES
RETHREADING DIE
Rethreading dies are used to restore bruised (rounded)
or rusty threads on screws and bolts. The rethreading
die is hexagonal in shape and may be turned with a
socket, box, open-end, or any other wrench that will fit.
They are available in American Coarse and Fine
Threads. Rethreading dies are available in a variety of
sizes and are usually assembled in sets with a case.
TWO-PIECE COLLET DIE
The two-piece collet die consists of the two die sections
the collet cap, and collet guide. The die sections are
placed inside the cap and held in place by the guide
Adjustment of the die is done by turning setscrews on
either end of the internal slot. They are used to cut
American Standard Coarse and Fine Threads and arc
available in assorted sizes.
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