A drill comprises of a cutting tool attachment called drill bit or driver bit fitted on a tool. It performs the dual function of boring holes in materials and fastening materials together using fasteners. The process of boring holes, slicing off shavings, crushing, and removing pieces of the work piece, counter boring, and other such operations are performed by the tip of this tool, which cuts into the target material. Masonry operations in mills or industries largely employ the use of drills, the hammer drill being the most common one.
The drill for Masons: Hammer Drill
The hammer drill is different from the conventional electric drill in regard to its hammer action for drilling masonry. Most electric hammer drills consume the input power between 600 to 1100 watts with a 50-60% efficiency rate. Thus, with the hammering action, 100 watts of input power is converted to 500-600 watts of input by a hammer drill. The hammering action of this drill is further measured in Blows per Minute (BPM). Mostly, 10,000 BPMs or more are commonly recorded. The standard masonry bits used are up to 13 mm (1/2 inch) in diameter, when combined with the chuck amounts to a combined mass, which is equivalent to the body of the drill, thereby, resulting in inefficient energy transfer and considerable vibration while in use. To help solve this, a pneumatic/rotary hammer employs a piston design in contrast to the spinning cam of the cam-type hammer drill and accelerates a little, producing much less vibration and penetrates the most building materials. Thus, its ability to drill holes is much better than the cam-type hammer drills and can bore large holes for installing large lead anchors in concrete for the benches or handrails or for lag bolts in foundations. The power of these rotary hammer drills can be seen by the fact that they use SDS or Spline Shank bits, as compared to the 6mm (1/4 inch) and 13 mm (1/2 inch) drill bits used in the standard Hammer drills.
The other kind of drills used for different purposes includes Magnetic drilling machine, Drill press, Cordless drill, Mill drill, Radial arm drill press, and so on.
Various Types of Materials for Drill Bits
Depending on the nature of the work and required application, the drill bits are available in different materials for effective results. A mason can choose the most optimal material according to its application:
- Low-carbon steel
These are used for drilling wood and are inexpensive. The drawback is that they require frequent sharpening and frequently working with hardwoods shortens its lifespan.
- High-carbon steel
They can be used on wood or metal and are more durable than the low-carbon ones. However, overheating may make them lose their temper and result in a soft-cutting edge.
- High-speed steel
These bits are harder and more heat-resistant than the high-carbon steel ones and it can drill metal and hardwood.
- Cobalt steel alloys
They contain more cobalt than high-speed steel, thus, it can drill harder materials like stainless steel, though they are more brittle than the former.
- Tungsten Carbide
This is an extremely hard metal. Therefore, it can drill almost every material. This feature makes it a relatively expensive material. They are used for drill-bit tips and in industries such as for PCB manufacturing.
- Polycrystalline diamond (PCD)
This bit is comprised of a layer of diamond particles about 0.5 mm thick, which are bonded to a tungsten-carbide support. Diamond being the strongest material makes a bit the hardest of all materials and extremely resistant to wear and tear. They are used in industries such as aerospace and automotive for drilling abrasive materials such as carbon-fiber reinforced plastics, aluminum alloys, and so on.
