Jet GHB-1330 Operating Instructions Manual page 7

- Start the machine at the lowest
spindle speed.
- When the tool reaches the end of
cut, stop the motor and at the same
time back the tool out of the part so
that it clears the thread (Attention
inertia: Stop the motor in time)
- Reverse the motor direction to allow
the cutting tool to travel back to the
starting point.
Repeat these steps until you have
obtained the desired results.
B) To cut metric threads with
threading dial:
On most metric threads the threading
dial (G, Fig 7) can be used.
The halve nut can be opened at the
end of cut, rather than the motor being
stopped and reversed.
The halve nut may only be engaged at
the corresponding graduation match
on the threading dial.
6.7 Drilling operation
Use a drill chuck with MT 3 arbour
(option) to hold centring drills and
twisted drills in the tailstock.
For recommended speeds refer to
section 6.4
To eject the drill chuck, fully retract
the tailstock quill.
7. Setup and adjustments
Warning:
Setup and adjustment work may
only be carried out after the
machine is protected against
accidental starting.
Press emergency stop button!
7.1 Change gear setup
Note:
The installed 36T x 127T x 48T gears
will cover most feeds and metric
threads.
The additional gears found in the
toolbox are used for inch threads and
some feeds.
Disconnect the machine from the
power source.
Loosen the locking screw on the
pulley cover, then open the cover.
-Loosen screw (D, Fig 18) and hex nut
(F) to disengage the quadrant.
Fig 18
-Change gears (G) to match the feed
and thread chart.
Adjust gears to mesh with upper and
lower gear.
Placing ordinary paper in between
gears helps to adjust for correct gear
spacing (... remove the paper
afterwards!).
Close and lock the pulley cover.
7.2 Turning between centres
Mount the workpiece fitted with the
drive dog between centres.
The driver is driven by the face plate
(Fig 19).
Fig 19
Lubricate the tailstock centre with
grease to prevent tip from
overheating.
9
7.3 Taper turning with tailstock
Turning up to a side angle of 5° can
be achieved by off-setting the
tailstock.
To offset the tailstock, loosen the
locking handle (I, Fig 8), loosen the
front adjusting screw (K) and take up
the same amount on the rear
adjusting screw.
Tighten the adjusting screws and the
locking nut to hold the tailstock in
position.
The work piece must be held between
centres and driven by the face plate
and drive dog.
After taper turning, the tailstock must
be returned to its original position.
Turn a test piece and adjust until the
machine turns a perfect cylinder.
7.4 Taper turning with top slide
By angling the top slide, tapers may
be turned.
Loosen 2 lock nuts (J, Fig 6) and
rotate the top slide according to the
graduated scale.
7.5 Three jaw universal chuck
With this universal chuck, cylindrical,
triangular and hexagonal stock may
be clamped (Fig 20).
Fig 20
To hold big diameter stock, reverse
the top jaws.
Use Molykote Paste G (or adequate
grease) to lubricate the jaws.
7.6 Four jaw independent chuck
(standard for GHB-1340A)