TM 9-3419-234-14&P
shut off. To start coolant flow, simply pivot the nozzle
(2) To change the gearing of a leadscrew machine,
toward the die head and coolant will flow automatically.
select the proper set of leadscrew gears by referring to
These nozzles are adjustable so the coolant can be
the gear table. Remove the gears which are to be
aimed directly to the chasers.
replaced and place the proper gears on their respective
(3) Coolant nozzles on double spindle machines may
studs. The gear train can be turned by hand so the
gears will mesh. (3)When setting up a machine for left
be operated independently of each other.
hand threading an additional 48T idler gear is needed.
m. Air Operated Carriage Fronts
Figure 14, Page 15, shows the location of this gear
(1) Air Pressure for the carriage fronts is obtained
through an air pressure regulator #421, Figure 21, Page
#228.
21. To set up a machine equipped with air operated
j. Automatic Workstop
(1) Automatic workstops #379, Figure 22, Page 22, are
fronts requires only that the proper air pressure be
established and the instructions followed as stated
furnished as auxiliary equipment.
(2) The cam, #345, Figure 22, Page 22, is positioned
under Die Head and Leadscrew Trip Mechanism.
on the bed to allow the workstop to be in the gaging
(2) To obtain the required amount of air pressure,
position when the carriage is at the rearmost or loading
rotate the handle on the air pressure regulator. A gage
position. As the carriage is moved forward, the cam
is mounted on the regulator to show the amount of
follower, #335, Figure 22, Page 22, starts up the cam
pressure being supplied to the grips. Enough pressure
should be maintained to prevent the workpiece from
incline and actuates the workstop moving it away from
slipping in the grips but low enough that they are not
the gaging position.
forced out of round .
(3) The workstop is mounted on a bar and is adjustable
(3) Air requirements for 10C-20C Machines are: 370
for gaging workpieces of variant lengths.
cubic feet of free air per hour for a production of 400
(4) The cam is also adjustable to eliminate
pieces per hour at 80 P S I at 21/2" stroke.
unnecessary carriage travel when cutting short thread
(4) On production runs it may be desirable to limit the
lengths. Simply loosen the screws in the cam bracket,
#344, Figure 22, Page 22, and reposition the cam on
opening and closing stroke of the grips. Instructions for
doing so may be found under Adjustments-Air Operated
the cam bracket.
Carriage Fronts.
k. Collet Chucks
(1) Collet chucks, Figure 25, Page 23, for 12C, 16C
n. Leadscrew Indicator Dial
(1) The leadscrew indicator dial, Figure 29, Page 25, is
and 20C machines are furnished as auxiliary
equipment.
a simple device which is attached to the carriage to
(2) The collet chuck is mounted on a special carriage
enable the operator to make a second pass over a
front and is operated by an operating lever, # 362,
thread without error. The indicator will show precisely
Figure 25, Page 23. A quick operating device, the collet
the point at which the leadscrew should be engaged so
the chasers will follow the original cut.
chuck is used on production runs on workpieces
(2) The indicator dial consists of a graduated dial and a
requiring a high degree of thread concentricity.
worm wheel which meshes with the leadscrew so the
(3) It is equipped with an adjustable workstop for fast
dial is revolved by the leadscrew when the carriage is
loading and a variety of collets to accommodate headed
stationary and, as the leadscrew nuts are engaged and
workpieces.
the carriage moved forward, the dial remains stationary.
(4) Setting up the collet chuck is a very simple
(3) When making a second pass over a thread, the
operation. However, it must be centered the same as a
carriage is returned to the loading position with the lead-
standard carriage front, instructions for which are found
screw disengaged. The leadscrew is re-engaged when
under "Adjustments."
one of the graduation lines on the dial is opposite the
I. Coolant System
zero line, thus causing the chasers to always follow the
(1) Fill the coolant reservoir until the oil level is just
under the surface of the coolant strainer, #322, Figure
original path.
13, Page 15,
(4) If the pitch of thread being cut is even, the lead-
screw may be engaged when any of the graduation
Coolant capacities are as follows:
lines are opposite the zero line, Figure 29, Page 25.
10C Pipe and Nipple, single spindle-18 gallons
10C Pipe and Nipple, double spindle-32 gallons
Odd numbered pitches require that one of the four
12C Single spindle-19 gallons
numbered lines be opposite the zero line. Even
12C Double spindle-35 gallons
numbered lines must be opposite the zero line when
cutting 1/2 pitches and line number 1 only when 1/4
16C Pipe and Nipple, single spindle-18 gallons
16C Pipe and Nipple, double spindle-36 gallons
pitches are threaded.
(5) There is no set reengagement procedure that will
16C Single spindle-20 gallons
16C Double spindle-40 gallons
universally work for all odd fractional pitch threads.
20C Single spindle-20 gallons
What will work, for example, when cutting 6.383 pitch
20C Double spindle-40 gallons
threads will not necessarily work for another odd pitch.
(2) A. coolant nozzle is provided for each die head and
Therefore, when cutting odd fractional pitches contact
engineering for the proper procedure to follow.
provides an ample flow of coolant. When the nozzles
are in a vertical position the coolant is automatically
5
