Jet GHB-1330 Operating Instructions Manual page 6

6.4 Spindle speeds selection
The correct spindle speed depends on
the type of machining, the cutting
diameter, the material to be machined
and the cutting tool.
These are recommended max. speeds
for a 50mm cutting diameter with
carbide (HM) tools:
Aluminium, brass
Cast iron
Mild steel
High carbon steel
Stainless steel
If high speed steel (HSS) tools are
used about 5 times lower speeds must
be chosen.
Generally speaking, the larger in
relation the cutting diameter, the
smaller the possible RPM.
For example:
Turning mild steel at a diameter of
25mm allows a speed of
1600 RPM max. with carbide tool
320 RPM max. with HSS tool
To change the spindle speed:
The speed may never be changed
when the spindle or motor are still
running.
Move the speed select levers (E, F,
Fig 14) according to the speed you
desire.
Fig 14
It may be necessary to turn the chuck
by hand to help the gears to engage.
6.5 Turning with auto feed
Several automatic longitudinal and
cross feeds (see Fig 15) are readily
available by selection on the gearbox
handles (D, H, Fig 14).
The feed direction can be chosen with
the feed reversing lever (G, Fig 14).
1500 RPM
1000 RPM
800 RPM
600 RPM
300 RPM
Further feed rates are possible by
different change gear setups.
Move the lever (D, Fig 16):
- right and up for longitudinal feed.
- left and down for cross feed.
The correct feed depends on the
material to be cut, the cutting
operation, the type of tool, the
rigidity of the work piece chucking,
the depth of cut and the desired
surface quality.
Fig 15
Fig 16
8
For example:
Longitudinal OD-turning, mild steel of
25mm diameter with a carbide tool at
1255 RPM and with rigid chucking.
Stock removal and roughing cut:
Depth of cut
Feed per revolution
(change gear box position B, D and R)
Finishing cut:
Depth of cut
Feed per revolution
(change gear box position A, D and R)
Micro finishing and calibration cut:
Depth of cut
Feed per revolution
(change gear box position B, C and R)
When roughing big diameters reduce
the depth of cut!
6.6 Thread cutting
Threading is performed in multiple
passes with a threading tool.
Each depth of cut should be about
0,2mm and become less for the
finishing passes.
Set the feed rate selectors (B, E, F, G,
Fig 17) in proper position.
Fig 17
Move the knob (C) to engage the lead
screw.
A) To cut inch and metric threads
Set the machine up for the desired
threading pitch and first depth of cut.
Engage the halve nut (H, Fig 16).
The halve nut must be engaged during
the entire threading process.
1,5mm
0,2mm
0,5mm
0.1mm
0,2mm
0.05mm