TM 9-3419-234-14&P
rigid holder support
special threads
k. The chaser holders are mounted on the face of the
taper threading
Die Heads. This design makes the chasers readily
c. Special chaser holders are required for generating
accessible for et-up changes and also provides the ample
special threads, when the helix angle is out of the range of
chip clearance so necessary for obtaining maximum tool
standard chaser holders. Limitations of each die head as
life. The chaser holders, attached to trunnions which
to the coarsest pitch threads that can be produced are
extend through the head body, am rigidly supported
included in the general specifications. However, coarser
between the trunnions and the sliding blocks which are
pitch threads than those listed can be cut provided the
mounted on the closing ring and operate in the tail slot of
form of thread is modified for depth. For complete
the chaser holders. The chaser holder mounting is such
information regarding special thread generation write to
that the holders and chasers are free to float axially, and
manufacturer giving complete details.
this insures proper "tracking" of the chasers.
I.
The 9/16" Head is furnished with the chaser holder
hollow milling cutters
and trunnion as an integral unit.
d. Hollow milling comprises an efficient, rapid and
The chaser holders are mounted on the face of the die
economical method of performing turning, forming and
head making both the chasers and holders readily
facing operations. The standard Heat Treated Die Heads
accessible for set-up changes when required.
lend themselves with little or no modification to hollow
milling operations on leadscrew type or hydraulic feed
machines. Multiple diameters may be turned with one set
of four milling cutters secured in a set of turning holders.
As with tangential die head chasers, the milling cutters can
be reground for a major portion of their original length.
e. The cutting rate realized from the hollow milling
method is approximately equal to the feed rate of a single
tool multiplied by the number of milling cutters contained in
the die head. The concerted action of the simultaneously
functioning cutting took results in an efficient and uniform
method of hollow milling.
Hollow Milling or Turning Cutters are available in a wide
variety of shapes, a few of which are illustrated above.
Fig 41
These cutters have the same outstanding long life
advantages as Tangential Chasers and enable high
SECTION VII
production turning operations at minimum cost.
Special Features
taper threading
a. Proper chasers and/or chaser holders are required
for general taper threading. However, if the die head is to
be used exclusively for tapered work, consideration should
be given to the S type Heads described on page 27 as
they are expressly designed for tapered threading.
b. For the smaller Head employing integral holders, the
same chaser holders are used to generate straight or
tapered threads as the taper, when required, is placed in
the chaser.
For the larger heads, chaser holders
machined to the required taper are necessary as the taper
Fig 42
is not placed in the chasers.
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