For best performance of Bi-Metal Hole Saws
- Wear safety glasses and keep idle hands away from the sawing operation.
- Apply sufficient feed pressure when sawing, about 80 to 100 pounds per inch of hole saw diameter. (More for harder materials, less for softer.)
- Be sure to fix arbor to hole saw firmly. Drive pins should be fully engaged in drive pin holes.
- Keep drive pins locked into drive pin holes with threaded retainer.
- Set the pilot drill point about 1/8" beyond the tooth points - enough to establish and hold a center.
- Chuck the hole saw properly.
- Hold hole saw and drive unit steady – drill press or lathe is best when possible.
- Use a good grade of cutting oil to assure cleaner cut and longer blade life.
- Hold saw perpendicular to the surface of material being cut.
- Operate hole saw at recommended speed.
- Run a hole saw too fast - it will cut faster at slow speed than at too fast a speed. If it runs too fast it will not cut, but wear out.
- Allow tooth points to rub over the work without digging in to take a chip. Rubbing the tooth points dulls them so they can't cut.
- Set the pilot drill point beyond the tooth points more than the thickness of the work. If the drill pierces the work before the saw teeth are in contact, the saw can hit the work with sufficient shock to break the saw or the teeth.
- Operate hole saw without cutting oil (except in cast iron) or the abrasion will cause enough heat to damage the cutting ability of the saw.
- Try to saw holes at an angle to the work surface. When teeth do not contact the work evenly the hole saw will be twisted out of round and will break.
- Allow hole saw and drive unit to wobble or orbit around pilot drill, as this sets up damaging stresses to strip the teeth or break the saw.
- Begin sawing with arbor so loose in cap that it will (1) tear out threads in saw cap, or (2) become inseparable (too tightly screwed in).
- Allow drive pins to retract from holes while saw is in operation. Loose drive pins can grind a hole in the cap.
- Chuck too loosely or off center. An improperly chucked hole saw will cause damaging vibrations.
- Let loose clothing or long hair get near a revolving hole saw.