tap is always used after the plug tap has been
the screw adjusting type is made by a fine-pitch
used. Both the taper and plug taps should precede
screw which forces the sides of the die apart or
the use of the bottoming hand tap.
allows them to spring together. The adjustment
Dies are available in several different
in the open adjusting type is made by three screws
shapes and are of the solid or adjustable type.
in the holder, one for expanding and two for
Figure 3-6 shows a solid type of rethreading die.
compressing the dies. Round split adjustable dies
It is used mainly for dressing over bruised or
are available in a variety of sizes to cut American
rusty threads on screws or bolts. It is available
standard coarse and fine threads, special form
in a variety of sizes for rethreading American
threads, and the standard sizes of threads that are
standard coarse and fine threads. These dies are
used in Britain and other European countries. For
usually hexagon in shape and can be turned with
hand threading, these taps and dies are held in tap
a socket, box, open-end, or any wrench that will
wrenches and diestocks (fig. 3-8).
fit.
THREAD CHASERS
Round split adjustable dies (fig. 3-7) are called
"button" dies. You can use them in either hand
Thread chasers are threading tools that have
diestocks or machine holders. The adjustment in
several teeth. They are used to rethread (chase)
Figure 3-7.--Types of adjustable dies.
Figure 3-8.--Tap wrenches and diestocks.
3-5
