(2) Adjustable dies.
(a) Round split adjustable dies. Round split adjustable dies (fig 32)
are called "Button" dies and can be used in either hand diestocks or machine
holders. The adjustment in the screw adjusting type is made by a fine-pitch screw
which forces the sides of the die apart or allows them to spring together. The
adjustment in the open adjusting types is made by means of three screws in the
holder--one for expanding and two for compressing the dies. Round split adjustable
dies are available in a variety of sizes to cut American Standard Coarse and Fine
threads, special form threads, and for the standard sizes used in Britain and other
European countries. For hand threading, these dies are held in diestocks (fig 33).
One type has three pointed screws that will hold round dies of any construction,
although specifically made for open adjusting-type dies.
Types of adjustable dies.
(b) Two-piece collet dies. A two-piece collet die (fig 32) is used with
a collet (fig 33). The collet consists of a cap and guide. The die halves are
placed in the cap slot and are held in place by the guide which screws into the
underside of the cap. The die is adjusted by means of setscrews at either end of
the internal slot. This type of adjustable die is issued in various sizes to cover
the cutting range of American Standard Coarse and Fine and special form threads.
Diestocks (fig 33) to hold collets are issued in three sizes.