How to sharpen drill bits on grinder

Start by holding the drill bit so that the cutting face is parallel to the grinding wheel surface, i.e. angled up, because you want to simply clean up the cutting edge to see what you’re doing.

Then slowly make contact with the wheel. Keep the bit as straight as possible, without rotating it. You want make a sort of flatter cutting face.

The heel of the cutting face needs to be grounded a little more than the edge so the cutting edge contacts the drilled surface first.

Bluing is a result of heat from the operator trying to take off too much metal with each pass. The bit will cut, but it won’t hold an edge as long.

So avoid bluing the bit. Sharpening drill bits removes metal, which causes heat. Some people dip the bit in water to cool it. If you can’t hold the bit in your bare hand, it may mean it’s too hot from grinding too fast.

When that cutting edge is sharp, flip the bit half a turn to sharpen the other side. Do not lift the bit to look at because you lose your hand position, just twirl it. Try to sharpen both edges evenly for best results.

Check to see that both sides are the same width by looking at the drill end-on. The two cutting edges should almost meet at a point in the center of the bit. If it isn’t, then grind slightly more to even them.

Just be sure the two edges are the same width, sharp and centered. Otherwise the point will “wander” when you use it.

If the bit doesn’t cut very well, you may have ground too much on the edge, compared to grinding on the heel. Regrind at a steeper angle.

And when you drill, clear out the chips off the bit flutes as you drill because that causes heat which reduces its performance and wears the bit.