Drill Rods – An Overview for You

A drill rod, made from high carbon steel, is used for manufacturing taps, drill bits, roller bearings and dowel pins. Drill rods are also needed for producing files, punches and hammers. The harness of steel used for the purpose varies with its carbon content. Generally, drill rods have a length of thirty-six inches with a diameter ranging from 1.5 millimeter (1/16″) to five centimeters (two inches), though you can also get these in longer lengths. The rod may be produced to have a square design.

Generally, we get two kinds of drill rods, namely oil or water hardened. The latter is used for the manufacturing of files and hammers, as the drill rod doesn’t contain many alloys. This facilitates the machining of materials, compared to the oil hardened variety. However, water hardened rods are not very appropriate for welding jobs. Drill rods which have been oil hardened can be welded, as well as machined easily. Its enduring hardness makes it very appropriate for the making of general tools.

The water hardening treatment involves the heating of the rod until it becomes cherry red, followed by dipping it in a container of water where it gets cool. This process creates a long lasting product which can be machined easily. Steel that has been heated to attain a cherry red color by being pushed into warm oil gives it an extremely tough surface, strong enough to break the majority of the cutting tools. That makes it imperative to give a machine finish to all such rods before pushing them into oil for the purpose of hardening.

Some rods need tempering before machining, according to their end use. The tempering of steel requires its reheating after it has been hardened in oil or water. After the steel has been heated to 426º C or 800º F, its hardness is slightly reduced, making it more workable. After the steel has reached that level of temperature and has been cooled in air, it can be polished.

The difference between oil and water hardening is the fact that water, being a far better conductor of heat, facilitates a quick cooling. However, parts should not be churned in water, as this encourages a quicker cooling on that side of the tool which is getting pushed through the water. When the rate of cooling on two sides is different, it results to warping. This plays a significant role when undertaking precision jobs. Steel needs to be dipped in straight up and down fashion for building a knife.