What are Step Drills?

Step drills are tools used in metalworking that typically come as a single drill bit with progressively sized ridges or grooves. The different sizes, known as “steps,” mean that just one tool can be used for a variety of settings; users can complete both bigger and smaller projects without having to switch implements. These sorts of tools are used in a variety of settings, but drilling holes in thin sheet metal is one of the most common applications. They’re also used with some regularity by auto mechanics, and can be helpful in countersink drilling, too. In general they shouldn’t be used on wood, mostly because of the risk of the wood splitting; they’re also best on thin materials. Within these parameters, they enjoy wide use and come in a number of different sizing specifications.

Most often, these sorts of tools are sold exclusively as bits. What this means from a practical perspective is that purchasers need to have a compatible drill already, or else buy one separately. Most bit sets are meant to be more or less universal, though, and will usually fit a number of different tools within their basic class.

The most distinctive thing about step bits is their sizing specifications. The bit usually has a cone shape that expands outward, effectively creating a range of different sizes all in one tool. In general it can contain anywhere from two to 13 different specifications, usually in increments of 1/32 inch to 3/4 inch (4 to 12 millimeters). There is some variance between brands and manufacturers, but in general these sorts of bits are rated to last up to six times longer than a conventional drill bit. They often cost slightly more, but the convenience of having a range of sizes together often makes it worth it.

By design, these drills are usually limited to use on thin materials. One of the most common applications is within sheet metal work. People working with sheet metal often need multiple-sized holes within a single project. Ordinarily, this would require the user to change drill bits over and over. Step drills can save time and expense over conventional drill bits in this respect. In most cases craftsmen use a drill bit with step increments slightly larger than the material’s thickness in order to get the best results.

Many custom sheet-metal fabricators have switched to step models due to their reliability and strength. In a fast-paced manufacturing environment, step drills have the potential of lasting much longer than a conventional drill bit. The thickness of the drill bit allows the drill to dissipate heat much better than conventional counterparts, too. This allows it to keep a much sharper and longer-lasting cutting edge, which often leads to cost savings for the manufacturer.

Beyond being a versatile drill bit, these tools can also serve as a countersink, which allows for screws and fasteners to be drilled below a given surface. This is really useful in many construction and engineering applications. Counterboring, which is the drilling of holes on opposite sides of a certain material, is another common use. The flexibility and sizing gradient of these tools makes it much simpler to drill a hole of one size on one side of a surface, then drill a hole of a slightly larger or smaller size on the reverse side. This technique is often used to strengthen bolts and attachments, and to provide added stability to certain construction endeavors.

Many automobile body shops use multi-stepped bits in auto-body restoration processes. Jobs such as the installation of chrome trim on exterior body panels often require different sized holes to be drilled into body panels. Using stepped bits allows the operator to produce these holes without changing tools or bit heads mid-stream. This often equates to improved production times.

Step drills are available in high-speed steel models as well as materials such as titanium. In general, titanium drill bits are best used on stainless steel, copper, brass and aluminum, or for drilling through thin plastics and laminates. The high-speed steel bits, by contrast, are typically best for thin steel and tin. No matter their material, in most cases all are laser-etched as to the different size drill measurements, creating an easy-to-read and easy-to-use tool.