Machine Operation - Jet BD-3 Operating Instructions Manual

6. Machine operation

Warning:
Setup, maintenance and repair work
may only be carried out after the
machine is protected against
accidental starting by pulling the
mains plug.
Check the save clamping of the work
piece before starting the machine.
Never stop the rotating chuck or work
piece with your hands.
Never place your fingers in a position
where they could contact any rotating
parts or chips.
Remove cutting chips with the aid of
an appropriate chip hook when the
machine is at a standstill only.
Always close the chuck guard and
pulley cover before you start the
machine.
Choose a small spindle speed when
working unbalanced work pieces and
for threading and tapping operations.
Never cut magnesium-
high danger to fire!
Measurements and adjustments may
be carried out when the machine is at
a standstill only.
In case of danger push the main
switch (emergency stop button).
6.1 Chucking
Never exceed the max speed
limitation of the work holding device.
Jaw teeth and scroll must always be
fully engaged. Otherwise chuck jaws
may break and fly off in rotation (Fig
3).
Fig 3
Avoid long workpiece extensions.
Parts may bend (Fig 4) or fly off (Fig
5).
Use tailstock or rest to support.
Fig 4
Fig 5
Avoid short clamping contact (A, Fig
6) or clamping on a minor part
diameter (B).
Fig 6
Face locate the workpiece for added
support.
6.2 Tool setup
The cutting angle is correct when the
cutting edge is in line with the centre
axis of the work piece. Use the point
of the tailstock centre as a gauge and
shims under the tool to obtain the
correct centre height (Fig 7).
6
Fig 7
Use both clamping screws when
installing the cutting tool to the tool
post.
Avoid big tool extensions.
6.3 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 speeds for a
10mm cutting diameter with HSS
(high speed steel) tool:
Aluminium, brass
Cast iron
Mild steel
High carbon steel
Stainless steel
If carbide tools (HM) are used about 5
times higher speeds can 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
20mm allows a speed of
400 RPM max.
2000 RPM max. with carbide tool
6.4 Manual turning
The handwheels (N, J, Fig 1) can be
operated for longitudinal and cross
feeding.
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.
When roughing big diameters
reduce the depth of cut!
1500 RPM
1000 RPM
800 RPM
600 RPM
300 RPM
with HSS tool