The Affordable Tool Harbor Freight Fans Love For Sharpening Lawn Mower Blades & More

You just wanted to sharpen your mower blades, and now you're online dealing with file people. These are metalworking's gruff, straight-to-the-point equivalent of woodworking's plane people. They understand every little intricacy of files and the materials — wood or metal — they're used to shape. They know why there must be dozens of designs, and what each is for. And because you're most likely to run into file people when researching them online, you might get the impression that, like planes, you should be prepared to spend a lot for a decent one.

But that's the wrong impression, and you can see that clearly in the quality and reputation of Harbor Freight's $3.99 Pittsburgh 8-Inch Flat File. For less than four bucks, you could be the owner of one of the best affordable Harbor Freight tools: a strong double-cut flat bastard file made of heat-treated high carbon steel, long enough to provide an easier time sharpening a mower blade, for example, but not long enough to get in the way.

But now you're probably wondering what all that means, and why I'd be so worked up as to call a file a flat bastard. A flat file is simply a file that's rectangular in cross-section, with both opposing faces being completely flat. "Bastard" is simply an old classification that describes a coarseness between "coarse" and "second cut" — a bastard by virtue of the fact that it is not fully one or the other, but is related to both. Double-cut means that its cutting face has two sets of teeth in a crosshatched pattern, and is a feature of files designed to use more force to remove more material.

People seem to like the Pittsburgh file. Reviewers on the Harbor Freight site give it 4.7 stars on 1,072 ratings, and 98 percent recommend it. That's about the same reception as the Kobalt 8-inch single-cut bastard-tooth mill file, $7.98 at Lowes. Purchasers who have taken time to write a review of the Pittsburgh file use it for all manner of things, from gunsmithing to fabrication to generic mechanic and metal work. But the majority of reviewers seem to have it for sharpening lawn and garden implements — mowers, shovels, that sort of thing. "Most budget priced files aren't all that great. This one IS great," one five-star reviewer on Harbor Freight's website assures us. "Sharpened my pruning shears and axes with this and it did awesome on both!"

Of course, suitability for purpose is a big part of quality, but this is Harbor Freight, and so we must also acknowledge that many reviewers were drawn to the low price and were subsequently pleased with the file's quality. One reviewer summed it up nicely: "For $4, it's not only a bargain but you can sharpen the blades in less than 2 minutes!" Lots of reviewers also enjoyed the textured and cushioned grip and even appreciated the PVC material, similar to the handle on the industry-standard Nicholson eight-inch flat double-cut bastard file, which retails for $12.65. The "handle is soft on the hands and easy to hold," says one reviewer. Another even compares it favorably to files with legacy: "I do like the handle, the older files I have lost the handles years ago. This file [cuts] way better than my old files I inherited from my dad."

When you've read enough tool reviews — or any reviews, maybe — one overarching pattern you notice is that there'll be hundreds or thousands of vaguely positive reviews, a handful of cranky but less-than-informative ones, and one critical reviewer that are well-considered, well-written, and usually reference information that not a single other reviewer even seemed to be aware of. It's tempting to think that single reviewer is right and the other 1,000 are wrong, but that's a matter of perspective.

We examined 125 of the 1,073 reviews for this file on the Harbor Freight site, and it was clear that a huge majority of the purchasers didn't have any idea what a bastard or a double-cut file is. They wanted to file something off of something else — usually metal, occasionally wood or plastic — and it worked for pretty much everyone, except that one guy.

In this case, that one guy appears to be a toolmaker who's forging steel and using the Pittsburgh file to remove scale (a byproduct of forging) and to roughly shape various grades of steel. The reviewer on Harbor Freight's site references a single-cut side (others say the file is double-cut on both sides) that's "not very good," and complains that one "can't [draw-file] as well as other single cut bastard files." But a reviewer on the Sawmill Creek woodworking forum compares the Pittsburgh file favorably to Nicholson's lawn mower blade files, saying that the Harbor Freight file is straight, thick, fully hardened, and cuts well. Two experts, two opinions. But 1,000 purchasers all agree that this tool is the right metal file for a wide range of applications, which is exactly what you usually need.