Machine Operation; Setup And Adjustments; Changing The Abrasive Wheel; Adjusting The Spark Guard - Jet JBG-150 Mode D'emploi

6. Machine operation

The bench grinder is designed for
grinding metal materials only without
use of water.
The Medium Grain Abrasive Wheel is
suitable for rough grinding where a
considerable amount of metal must
be removed.
The Fine Grain Abrasive Wheel is
suitable for sharpening tools and
grinding to close size and smooth
finish.
Hold and guide the workpiece safely
during machining.
Do not perform any operation
freehand; always have the workpiece
supported by the tool rest.
Apply a moderate pressure on the
workpiece and keep it moving for
smooth grinding.
Pressing too hard overheats the
motor and prematurely wears down
the grinding wheels.
Note the original bevel angle on the
item to be sharpened and try to
maintain the same shape.
The grinding wheel should rotate into
the object being sharpened.
Keep a tray filled with water and dip
your workpiece regularly to prevent
overheating.
Overheating can weaken metals.
When the wheel becomes loaded of
debris, use an approved grinding
wheel dresser and dress the wheel.
Warning:
The condition of the abrasive wheels
should be checked before each
machining process.
Work only with flawless abrasive
wheels.
Do not allow anyone to stand behind
the unit or close to the workpiece
where debris can be thrown.
Flying sparks will occur when cutting.
They can cause injury and ignite
flammable materials.
Use safety goggles at all times.
Use ear protection at all times.
Wear a face and dust mask when
working in a dusty environment.
Ensure that the wheel guards are in
the correct position before you start
machining.
Keep the tool rest and spark guard to
within 2mm of the grinding wheel.
Before starting the grinder, turn the
wheels by hand making sure they
turn freely.
Allow the abrasive wheels to reach
full speed before machining.
Do not use the side of the grinding
wheel; this puts dangerous stress on
the wheel.
Do not stop the wheel by side
pressure.
Do not touch the machined workpiece
until it cools or you may be burned!
Never place your hand near the
cutting area while machine is in
operation.
Never machine pieces that are too
small to hold safely.
Support long work pieces with helping
roller stands.

7. Setup and adjustments

7.1 Changing the abrasive wheel

The abrasive wheel may
only be changed when
the mains plug is pulled!
The abrasive wheel has to meet the
technical specification.
Use only abrasive wheels rated at
3000 RPM or higher.
Check abrasive wheel for flaws
(cracks) before installation.
Make the ring test.
Ring test:
An internal defect may not be
apparent by visual inspection alone.
The ring test may uncover an internal
crack or void.
Loop a piece of string through the
grinding wheel hole and suspend the
wheel.
Tap the wheel with a piece of scrap
wood.
A good wheel will "ring"; a defective
wheel will "thud".
Do not use a wheel that does not
"ring".
To change a wheel:
Disconnect grinder from the power
source.
Move the tool rest (C, Fig 4) and the
spark guard away from the wheel.
6
Fig 4
Remove the wheel cover.
Remove the nut (P), clamping flange
(O) and abrasive wheel (Q).
Note:
Turn the nut on the right-hand wheel
counter-clockwise to loosen.
Turn the nut on the left-hand wheel
clockwise to loosen (left hand thread).
Clean flanges.
To install the new abrasive wheel
reverse the process.
Do not over tighten the nut; this may
cause the wheel to crack.
Replace the wheel cover.
Adjust the spark guards and tool rests
to a 2mm clearance from the wheel.
Plug in.
Before starting the grinder, turn the
wheels by hand making sure they
turn freely.
Run the unit and check to make sure
the abrasive wheel is in good
condition.
When testing a new abrasive wheel,
run the unit for 3 minutes.
Note:
Always stand on one side when
turning on the unit.

7.2 Adjusting the spark guard

As the wheel wears down, the spark
guard must be re-adjusted to
maintain a maximum 2mm clearance.
Loosen screw (K, Fig 5) to adjust.