By Grainger Editorial Staff 5/25/23
Drill bits come in a wide range of shapes, sizes and lengths and are available in a variety of materials and coatings. For metals and plastic, drill bits have cutting edges designed to remove material as they rotate to create holes, and in the case of plastic, will also prevent cracking a workpiece. There are other drill bits whose cutting edges are specifically designed to tackle glass, tile and porcelain, masonry and concrete and wood.
The following drill bit properties, including the materials they are made of, flute designs, point angles, lengths and coatings are commonly found in bits designed to drill plastic and metals. Drill bits with varying combinations of these features are chosen for how well they perform specific tasks and how well they work for the strength and thicknesses of substrate. Here’s a quick rundown of these features and how typical uses for metals and plastic.
Another consideration when choosing drill bits is the flute design. Here are the two most common designs:
The two most common point angles for metals are 118 degrees and 135 degrees. The sharper 118-degree angle is best used for softer metals. Harder metals will wear the bit faster. The 135-degree self-centering point angle is flatter, putting more of the bit in contact with the substrate. Sometimes a bit with a 135-degree point angle tends to move around or “walk,” so tasks on harder metals with these bits may require a pilot hole to get the drill bit started.
If a shorter drill bit can do the job, it’s a better option. Shorter drill bits are more accurate and because they’re more rigid, they don’t break as often so you can use less and therefore spend less. Shorter drill bits are also better in tighter, more confined areas. Here are a few of the most common varieties:
The primary purpose of a drill bit coating is to provide a protective shield that improves cutting performance of the bit, extending the life of the tool. Some coatings have specific functions. For metals and plastics, here are some of the more common coatings and the benefits of each.
Choosing the right drill bit for the task is an important part of any project or application. Whether it’s matching the appropriate bit to the substrate material, getting the right match for the depth and diameter of the hole needed, or even the volume of work, the right choice can extend the life of your drill bits and your tools.
Stop by the KnowHow equipment page for more tips on tools and supplies.
The information contained in this article is intended for general information purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. Readers with specific questions should refer to the applicable standards or consult with an attorney.