My father always told me that you need to have a couple of good files around. So whenever we used to find ourselves walking together around the flea market or tool shop putting together a toolkit for my apartment or car, he’d suggest I add a file or two.
I’m embarassed to admit that even though there are files in every toolkit I’ve ever owned, I’ve never really used them much. That all changed yesterday when I needed to create a small rectangular hole in a piece of 1″ x 1/8″ steel bar stock.
I tried numerous different techniques, but the one that truly worked well was drilling a hole to the correct diameter and filing it square. After spending a few hours of quality time with the drawer full of files I inherited from Dad, I’ve found lots and lots of uses for them in the shop and home, and now I finally understand why he was such a file fan. I am, too.
As the file is an extremely old tool, there are lots of odd and technical names for every variation in shape, size, teeth, and intended material. There are lots of articles out there on the ‘net that can clue you in to the details, and I’ve linked some of them at the end of this post. Here, however, is the layman’s summary:
Files generally come in a few standard shapes: flat (the one you think of when someone says “file”, round (sometimes called a “rat-tail” file for obvious reasons), half-round (one side’s flat, the other side’s round), and triangular (called “taper”). Files with more and smaller teeth remove less material on each file-stroke while files with fewer and larger teeth remove more. You’ll commonly see files divided into three categories as far as the size/spacing of their teeth are concerned. From smallest/most to largest/least teeth, they’re called: smooth cut, second cut, and bastard cut.
You’ll also see flat files with “cut edges” which means that the small edge of the file has teeth cut into it. “Uncut edge” files do not.
Like with most hand tools, you have to spend a little time using them to really know what you can do with them. But once you do you’ll find all kinds of uses. In the shop I use a file to quickly deburr the edge of a piece of metal that just came out of the bandsaw. On smaller pieces, I’ll clean the edge up slightly with a file before welding. (Sure, you can do this with an angle grinder — I used to — but it only takes a few seconds longer with a file and you have much, much more control, resulting in the removal of less metal to get the job done.) The same applies to getting just the right fit when welding tubing together.
In the house, the right file works great for removing just a little wood to get a new doorknob assembly to fit, or to modify clearance on plastic items. Totally rounded off a nut? File it square and give it another go with an open-end wrench.
As you spend more time with your files, you’ll start to get a grasp for which one’s best for the job — or more likely, which ones are best for the job. I find myself often grabbing a couple of files from the drawer instead of just one.
For example, to make a square hole, I’ll grab an appropriately-sized taper and a couple of various cut flats. The triangularly-shaped taper is great for cutting the corners, and once the hole’s square and large enough, you can use the rougher flat to open it up close to the size you desire and a smoother flat to finish it out.
When you get really proficient with your files, you can do some pretty amazing things. At an amateur telescope building meeting, I saw an incredible telescope mount that incorporated lots of little “machined” aluminum parts — but they guy who built it didn’t own a mill. He created them all with a hack saw and files… and a lot of time.
I’m not suggesting that you throw out your grinders and sanders, but why not take a little time to practice with your files, too. And when you’re putting together a toolkit for the home or car, include a file or two. You won’t regret it.
Files & Rasps [This Old House]