Which drill bit is best for hard rock drilling?

Keep constant down pressure and do not allow the drill to bounce in the hole and H thread should work very well in most hard rock drilling applications. This bit has 4 large silver brazed carbide inserts that hold up extremely well in production hard rock drilling applications.

What is drill steel & how does it work?

The drill steel is normally carburized which is a process of infusing the steel with carbon elements in a furnace. This gives the steel an extremely hard casing while maintaining a lower hardness inside to transfer the impact shockwave. The thread is larger/longer and will bottom out inside the rock bit.

How deep can a drill hole be drilled?

Small holes can be quickly attained with pneumatic drills. Typically from 5/8” to 1” diameter up to 26” depth – but larger/smaller diameters and depths may be available. Cost more than a separate steel and bit. The size of the steel decreases with the bit size - so the column strength decreases as well.

What is tapered drill steel used for?

Tapered drill steel was/is primarily used in underground mining on jackleg drills. 12 degree taper is more prevalent in Canada and 11 degree is more prevalent in the US and Central America. The female tapered bit pushes on to the male tapered drill steel. Once mated – they can be separated by means of a bit knocker when the bit is worn out.

How long does a jackleg drill last without a carbide component?

Without the carbide component you can expect a relatively short lifespan especially in abrasive conditions. Tapered drill steel was/is primarily used in underground mining on jackleg drills. 12 degree taper is more prevalent in Canada and 11 degree is more prevalent in the US and Central America.

What size drill shank do I Need?

When you move to the bigger hand held drills, there are only 3 common shank sizes. 7/8 x 3 ¼”, 7/8 x 4 ¼” and 1 x 4 ¼”. These measurements refer to the diameter of the hex steel (measured across the flats) and the length above the retaining collar.