The drill is one of the most common tools for use in metalworking, construction, and woodworking projects. This versatile tool allows the user to fasten materials together and bore holes. Drill machines are rated for power and capacity depending upon usage.
There are many types of drills from which to choose. Conventional types include manual drills which are used to manually bore into materials, electric drills that use some form of electricity, and pneumatic drills which operate via compressed air.
In addition to the three conventional drill types noted, certain industries use highly specialized drills such as earth drilling augers which utilize internal combustion for boring operations and hammer drills which use percussive actions to drill through concrete, stone or brick.
History of Drill Bits
Drill bits date back to prehistoric times. Historians believe that as early as 35,000 BC Homo sapiens discovered the usefulness of rotary tools for boring into materials. Early man used smooth sticks with a flint point attached to create the necessary holes. By the late Paleolithic era, man moved on from using flat sticks with stone points to bone, shells, and even antlers to do their work.
Ancient Egyptians used wood as their primary drill bit instead of bone and shells. The user attached strings to the end of a bow then wrapped the remaining end around a stick. The bow would then be moved back and forth to create a rotary motion. While the primary purpose of the wooden drill bit of this era was to build a fire, there is evidence that Egyptians also used these drills in woodworking, dentistry, and stone-working.
It was not until the 13th century that man began using metal pieces as drill bits. Inventors discovered that if they used pieces of copper inside of the tubular stick, they could drill a hole by grinding the outer section of the area. This discovery allowed them to minimize the damage to materials when making the desired size hole.
Since the discovery of metal tooling, drill bit sizes and styles have evolved. Drill bits come in the traditional spiral shape as well as in conical, core, and spade shapes. The diameter and length for each of these types varies by the intended use. Additionally, materials used to make the bits range from high and low carbon steel to carbides and diamonds.
In simple terms, drill tooling function was originally designed to do one thing, create a hole in a work-piece. Today, in addition to just creating new holes in a work-piece, drills also perform other essential aspects of the boring operation. These tasks follow the initial drilling process.
- Tapping: Provides internal threading in a drilled hole;
- Countersinking: Produces a step in the drilled hole to allow a bolt head to seat below the surface, at an angle;
- Counterboring: Creates a step in the drilled hole to allow a screw head to seat below the surface, straight hole;
- Reaming: Enlarges a previously drilled hole.
Drilling completes two other functions which precede creating the hole. These are:
- Spotfacing: Provides a flat machined surface on the work-piece;
- Centering: Accurately locates the hole for drilling.
The drill classes differ depending upon the type of work-piece bored or the operation conducted. An example of this is the crankshaft drill. Crankshaft drills are specialized tools used to create oil holes in a crankshaft. These tools machine deep holes through harder materials. The helix angle on this tooling type is higher than traditional drills.
Another standard drill class is the oil hole drill. This tool, as the name implies, cuts small holes in the land. These holes force pressurized oil to the tool point.
Modern technology allows these devices greater power and longer life. Innovations such as brushless motors offer less resistance during use. These engines also use less energy, drawing what charge they need to power the windings and magnets. Users notice a greater voltage as there is a little drop-off.
This increased voltage is due to there being no brushes to create friction while dragging against the commutator, another piece that is no longer needed.
Industries, such as automotive manufacturing, have seen increased productivity thanks to innovations in drill tooling. Each vehicle requires hundreds of holes drilled throughout parts of the engine, crankshafts, transmission shafts and other areas. Using high-speed tools with appropriate bits streamlines the cutting process.
Additionally, the use of stealth drill technology allows the drill to run straighter for longer. This action produces better hole formation and evenly wears the bit to reduce chip formation.
In fracking, hybrid tooling allows for a simplified drilling process. Hybrid tools are deployed in sequence and allow drilling and tubing the hole in one pass. Not only does it simplify the process of drilling and pipe, but it maintains a pipe-heavy condition during the procedure. A pipe-heavy condition eliminates tube ejection and potential injury.
Like all machinery, the maintenance of tooling equipment is key to its longevity. Following the manufacturers’ guidelines is a good place to start when performing maintenance on equipment. Also, routine checks on bits and other parts are necessary. Always follow the stated guidelines on machinery and attachment use.
Pay careful attention to work-piece warnings as some drill tools may not be rated to penetrate all materials.
Lubricating tooling equipment regularly, with the manufacturer specified lubricant, helps to keep the motor running at peak efficiency. Also, larger drills, such as ground boring drills, may need fluid to reduce the amount of wear on the drill pipe. Use of this particular drilling fluid always, no matter the depth of the bore, can make the equipment last longer.
For boring ground drills, know the soil conditions before beginning. Understanding the composition of the soil and whether rocks or boulders are present ensures the proper use of drill bits (see more about this in Why a Detailed Geotechnical Report Means Success for Your Trenchless Project). Using the wrong tooling and fluids can damage the equipment.
The biggest challenges facing drill tooling is knowing what type of equipment to use. The kind of drill and drill bit needed depends heavily on geometry, work-piece material, and the overall unique aspects of a project. Each different type of drilling job presents its specific challenges (read about the 5 Pipe Ramming Methods Used in HDD) .
Deep-hole drilling has its own set of difficulties. These drilling tools must find a way to evacuate material chips without damaging the surrounding surface. Additionally, they must address the problem of delivering coolant to the drill in to keep the machine and work-piece from overheating. An internal cooling system can address both difficulties. In the event the bit is too small for an internal cooling system, coating the tool can help keep the tool cool while controlling material chips.
Despite its humble origins, a drill is a precision tool that allows users to bore and fasten many types of materials.