BM 1609929H55 1-05 1/5/05 3:17 AM Page 11
SANDING WOOD
When sanding wood the direction of the disc motion at the contact point should parallel the grain as much as possible. The rapid cut of discs and the swirl type scratch pattern they occasionally create generally prohibit their use for producing the final finish.
Scratches and circular marks are usually the result of using too coarse a grit. When changing to a finer grit, move across the sanding lines that were made by a previous coarser disc.
SANDING METAL
When sanding automobiles or appliances, wipe the metal clean with a
For heavy duty work, use a coarse grit disc first.
Grinding Operations
SELECTING GRINDING WHEELS
Before using a grinding wheel, be certain that its maximum safe operating speed is not exceeded by the nameplate speed of the grinder. Do not exceed the recommended wheel diameter.
DISC GRINDING WHEELS
Grinding wheels should be carefully selected in order to use the grinder most efficiently. Wheels vary in type of abrasive, bond, hardness, grit size and structure. The correct type of wheel to use is determined by the job. Use disc grinding wheels for fast grinding of structural steel, heavy weld beads, steel casting, stainless steel and other ferrous metals.
GRINDING TIPS
Efficient grinding is achieved by controlling the pressure and keeping the angle between wheel and workpiece at 10° to 15°. If the wheel is flat, the tool is difficult to control. If the angle is too steep, the pressure is concentrated on a small area causing burning to the work surface.
| Excessive or sudden | |
! WARNING | ||
pressure on the wheel will |
slow grinding action and put dangerous stresses on the wheel.
When grinding with a new wheel be certain to grind while pulling tool backwards until wheel becomes rounded on its edge. New wheels have sharp corners which tend to “bite” or cut into workpiece when pushing forward.
Wire Brush Operations
Wire brushes are intended to “clean” structural steel, castings, sheet metal, stone and concrete. They are used to remove rust, scale and paint.
Avoid bouncing and snag- ! WARNING ging the wire brush, espe-
cially when working corners, sharp edges etc. This can cause loss of control and kickback.
BRUSHING PRESSURE
1.Remember, the tips of a wire brush do the work. Operate the brush with the lightest pressure so only the tips of the wire come in contact with the work.
2.If heavier pressures are used, the wires will be overstressed, resulting in a wiping action; and if this is continued, the life of the brush will be shortened due to wire fatigue.
3.Apply the brush to the work in such a way that as much of the brush face as possible is
in full contact with the work. Applying the side or edge of the brush to the work will result in wire breakage and shortened brush life.
CORRECT: Wire tips doing the work.
15°
INCORRECT: Excessive pressure can cause wire breakage.
