Common Questions and Answers

Do I need thru-the-spindle coolant? 

We do recommend it, but it's not necessary. It's important though to flood the drill with external coolant if your machine does not have thru‑the‑spindle coolant. Your drilling depth might be limited without through the spindle coolant.

Do I have to peck the drill?

No. You do not need to peck the drill unless you exceed the recommended drilling depth or large chips are packing in the flutes due to the material.

Do I use a Center drill?

No, it is not necessary.

Why aren't the chips breaking up?

The main factor in stringy chips is the material. If your machine has the additional horsepower, increase your feed rate. This will help in breaking up the chips.

Why am I stalling my spindle?

Carbide insert drills can use tremendous amounts of horsepower. If you are using a large diameter DORA‑HOG drill, you may be exceeding the limits of your machine. Try these solutions . . .

1). Place your machine in the lowest gear range if available.

2). Slow the feed rate.

3). Try a smaller diameter drill and bore diameter up to size.

How can I avoid chips from welding to the sides of my drill? 

(also called galling)

Some materials (like 1018 and A36 material) are prone to creating stringy, coarse chips that are hard to evacuate. These chips wrap themselves around the drill and weld themselves to the part and drill causing loud pops and screeches. A solution is to grind or turn the O.D. of your drill behind the inserts to allow extra chip clearance.

Why is the drill chipping on the inside insert near the center?

The relative surface feet per minute at the center of the workplace is zero and the insert is pushing the material instead of cutting the material. This causes the inner insert to chip at the center on certain materials. The insert life is generally not reduced because of the chipping. If the insert life is reduced, here are some solutions that may help . . .

1). On turning centers, a possibility may be that your turret is not properly aligned. We suggest rotating the drill 180°.

2). If using coated inserts, switch the inner insert to an uncoated one. The uncoated insert is more tolerant of this problem.

Why is the drill cutting oversize on my turning center?

Misalignment of the turret or the machine holder are some factors. Material is another. Here are some solutions . . .

1). Rotate the drill so the inserts are aligned with the X‑axis, placing the outer insert in position like a boring bar. Then just use your offset to compensate.

2). If turret misalignment is the cause, rotating your drill 90° or 180° will help correct the problem.