Forget Dull Drill Bits: Easily Sharpen Them With These Amazon Finds For Under $40

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Dull drill bits can be extremely frustrating. When drilling into wood, a dull bit can take forever, and it might even threaten to set your workpiece on fire as the dull bit generates more friction and heat. When drilling into metal, a dull bit may do nothing but make a little dent and then ruin itself. Given the cost of decent bits, it makes sense to sharpen them... But not if the process is too time-consuming or the sharpening tool too expensive. We've tracked down five sharpeners under $40 on Amazon that all accomplish the same thing in slightly different ways, from an $11.99 Dremel attachment to a few freestanding electric sharpeners costing up to $39.99.

In general, sharpening a standard twist drill bit involves removing material from the bit's relief faces to create a symmetrical point angle that matches the original, usually 118 degrees. You can do this freehand using a tool like a bench grinder, with the assistance of a 3D-printed or other homemade jig. But, of course, you can also sharpen drill bits without a bench grinder, using a device that helps you achieve the correct angle. More advanced freehand sharpeners can even reshape a bit's chisel edge into a split point. There are a few differences between split-point drill bits and standard bits, but split-point bits are usually ground at a 135-degree angle rather than 118. Inexpensive sharpener models do not generally cut split-point tips, though more expensive models often do. But given the average price of the top-rated sharpeners on Amazon, around $150, many of us will be perfectly happy with a sub-$40 sharpener and the standard bit geometry.

The MDPSDS Electric Drill Bit Sharpener, like most $40-and-under sharpeners on Amazon, is one of several apparently identical models offered by different sellers. This $39.99 sharpener is reviewed reasonably well, with 4.3 stars on over 170 ratings. The MDPSDS sharpener is a freestanding device that works on household power and uses a replaceable brown corundum grinding wheel to sharpen 19 bit sizes, from ⅛ to ¹⁵⁄₃₂ inch. The manufacturer claims the device will sharpen any bit, including those made of high-speed steel, carbide, hardened steel, and high carbon steel. It sharpens bits to a non-standard 130-degree angle that's most suitable for drilling into hard steel and alloys. The device has a non-slip base and operates with a simple-to-use on/off switch.

To operate it, you insert your bit into the appropriately sized hole, then adjust the grinding wheel position so that it's making contact with the bit. Then grind the two cutting edges one at a time until the bit is sharp. MDPSDS claims this takes 10 seconds, but Project Farm tests found that a similar model from Leiming took about two and a half minutes to sharpen a very damaged bit. Because of the non-standard angle, the bit came away with a different geometry that caused it to cut through mild steel faster than the factory geometry.

This 95-watt generic electric drill bit sharpener for 3 to 12 millimeter bits is also a wall-powered, freestanding sharpener. At $39.99, it has 3.8 stars from more than 50 ratings and sharpens at a standard 118-degree angle; the 3 to 12 millimeters translates to a range of ⅛ inch to ¹⁵⁄₃₂ inch. The device's built-in motor runs at 1,500 RPM. A few Amazon reviewers note that the machine comes with operating instructions that are less than useful. But most found the device sharpens bits well overall, though some noted that the grinding stone leaves a somewhat coarser finish than the bits' factory points.

This generic sharpener and at least one other model are identical in design and specifications to a $57.99 Truper model with 4 stars from more than 170 ratings. Project Farm also tested the Truper model, and if the actual performance of the generic model is the same, it might be the best of the bunch. The Truper model was the second fastest through ½-inch mild steel after sharpening, including a second test cut, and performed faster than the factory-sharpened bit.

The 96-watt DRRSBRP adjustable angle multifunctional bit sharpener is one of many apparently identical models sold at different price points on Amazon, often well above our $40 threshold. This particular version has 5 stars and costs $35.60, though it only has two ratings at the time of writing. But similar models with more ratings tend to run 3.5 to 4 stars and are priced around $50. The plug-in sharpener runs at 1,350 RPM on four anti-slip feet. It has a 15-to-50-degree adjustable angle and various positions for sharpening additional tools, including planer knives, scissors, chisels, knives, and other blades. It sharpens drills from 3 to 13 millimeters.

Operation of the DRRSBRP and similar models is a bit more complicated than many other devices. Drill bits are placed into a carriage assembly, and then a slot in the machine is used to position the bit properly. The carriage is then moved into the sharpening position, and the bit is sharpened as the user rocks the sharpening apparatus side to side. Then you flip over the carriage and repeat the rocking motion to sharpen the other side of the bit.

Seemingly identical models with more reviews have some common complaints that might also apply to this one. The most common complaint is about the build quality, with reviewers finding the plastic too flexible to serve their purposes well. Reviewers of more than one model note that there's a lot of play in the sharpening mechanisms, which can lead to tool damage.

In addition to freestanding electric bit sharpening tools, there are many that require an external source of grinding power, like a drill, angle grinder, rotary tool, or bench grinder. The General Tools drill grinding attachment #825 is a bench grinder attachment, so it won't be of use to anyone without one. But it's a novel approach from a reputable, highly rated brand, and at $30.79 with 4.2 stars on more than 1,300 ratings, it's worth a look. It supports standard angles of 88, 68, 59, 49, and 41 degrees. Note that this is the angle between the side of the bit and the side of the grinding wheel, so 59 degrees corresponds to the normal 118-degree sharpening angle (118 degrees halved). Based on reviews, it seems to operate best in the ⅛-to-½-inch range, very similar to other sharpeners, though some users report success up to ⅝ inch. The sweeping motion curves the sharpened face for a proper relief angle behind the cutting edge. The pivot also ensures, critically, that both sides of the bit are sharpened symmetrically.

Because this General Tools sharpener relies on grinding via the side of a bench grinder's wheel, be sure to use a wheel specifically designed for that approach. The General Tools #825 will need to be mounted on your bench grinder at a specific distance. Setup is a bit more complex with the General Tools #825 than with other types of sharpeners. Fortunately, the included manual does a reasonably good job of explaining the mounting and setup clearly.

The SplashNColor rotary tool drill bit sharpener guide, unsurprisingly, requires a rotary tool like an old-school Dremel. It screws onto the M19-2 attachment threading found at the business end of most rotary tool models and provides guides so that you can properly sharpen your bits at one of three angles: 90, 118, or 135 degrees. The SplashNColor appears to be 3D printed with ABS, a light and strong plastic that should hold up well to the operation. Versions printed with PETG filament have notably lower ratings. This rotary tool attachment costs $11.99 and has 5 stars, but only two ratings on Amazon. To use the SplashNColor guide, you'll also need a reinforced abrasive wheel against which to sharpen your bits. There is no indication of what bit sizes are supported.

To use the SplashNColor, mount it to your rotary tool, then chuck in the abrasive wheel of your choice. (It's probably inadvisable to use non-reinforced cutoff wheels, which are prone to shatter under the best of circumstances, and almost certain to when pressure is applied to their sides.) Slot your bit into the appropriate guide for the angle you want, turn on the tool, and grind the bit point against the abrasive wheel until you're satisfied with the sharpness. Attachments like this add a surprising amount of functionality to rotary tools, allowing them to accomplish everything from polishing stones to sharpening chainsaws quickly.