Burr King Model 20 - Manual (Page 8)

See our catalog at www.burrking.com Contact us at [email protected] 2
2. Verify that the disc spins freely. Note that on models with motor brakes the disc will be locked. At the
rear of the motor you will find a control that when rotated will free the brake to rotate. This control
should be left in the locked position for normal operation of the machine.
3. Verify that the gap (nip point) between the PSA abrasive disc and the table edge next to the front of the
disc is less than 1/8 inch. This gap is set at the factory to comply with this requirement. The gap should
not change unless table erosion occurs, maintenance to the machine is attempted, or damage has
occurred.
4. To install or remove an abrasive disc push the disc guard to its rear most position. Install the PSA disc
taking care to position it concentric to the aluminum backing disc.
Note: To remove or replace a PSA disc it is necessary to lower the disc grinder table clear of the aluminum
backing disc. To do this first unlock the table by loosing the table clamp at the rear of the machine. Lower or
raise the table by rotating the large hand wheel to the right of the table.
Note: PSA abrasive discs can leave a residue on the aluminum backing disc. Normally this can be cleaned
with isopropyl alcohol and a soft rag.
Note: Do not spin or otherwise force the table mechanism to the end of travel up or down. To do so
may shear keepers, shafts, or gears inside the table gear box. Always secure the table with the table
locking clamp before using the model 20 grinder.
5. As before assure that the disc spins freely.
6. Loose the table locking knob to the left of the table. Using the small hand wheel to the right of the table
verify that the table can be angled in respect to the disc. Always re-lock the table.
Grinding modes
1. The direction of disc rotation determines the point of grinding.
Never grind on the side of the disc where the movement of the abrasive disc is upward from the table.
Doing so may create an operator hazard from debris, and or ejected work pieces.
2. Supported work: Always use work piece holding devices to minimize the risk of operator contact with
the rotating abrasive disc.
3. For controlled angle grinding tilt the table down to any angle from 0 to 45 degrees. Read the angle on the
indicator found on the small hand wheel. Note: Use of a precision protractor is recommended where
angles of plus/minus 2 degrees are required.
4. Use the available miter attachment for grinding compound or other angles.
5. Use reduced disc speed (variable speed models) for many materials where abrasive speed is critical. The
abrasive speed at the outer disc perimeter is approximately 9000 SFPM at 1750 RPM.
Note: Never grind with the table tilted in an acute angle (up) in respect to the disc while holding the
work piece by hand. The disc may seize the part stall the machine, and or injure the operator. This
operating mode should only be used where the work part is firmly secured to the table as in bolting,
clamping, etc. and the operator is well protected from potential injury.
Note: Never position work pieces at an acute up angle with disc with the table at any angle.
Doing so may lead to serious operator or bystander injury.
Note: Never grind material that is less than ¼ inch thick in its smallest dimension with out the use of
work piece holding devices that protect the operator and bystanders. Doing so may lead to serious
operator or bystander injury.
Beware that thin (less than ¼ inch) material can lodge in the gap between the table and the disc
creating a potential for serious injury, and/or property damage.
Maintenance for the model 20
ALWAYS DISCONNECT THE MACHINE FROM ITS AC POWER SOURCE PRIOR TO
CHANGING THE PSA DISC OR PERFORMING MACHINE MAINTENANCE.
1. Vacuum or otherwise remove dust and debris build-up from the machine.