Woodworking Tools: Rasps

By December 3, 2017Uncategorized

Most rasps are around 8 "to 12" long and come in coarse, bastard, second-cut, and smooth grades. You may also see them described as either a wood rasp, a cabinet rasp, or a pattern-maker's rasp. Wood rasps are the most aggressive of these and usually come with a bastard cut in either flat or half-round profiles. Cabinet rasps are typically second-cut or smooth and also come in half-round and flat (half- round being the more common). Pattern-maker's rasps are also available in second- cut and smooth, and they generally have smaller teeth that tend to leave a smoother finish than the cabinet rasp.

One of my favorite rasps is a 4-in-hand rasp (originally called a shoe rasp). This handy tool combines four tools in one, as you've guess from the name. Its doubled-ended with a half-round shape. One end is a rasp, the other a file – you'd think they'd call it a 4-in-hand rasp / file.

Effectively, you have a half-round file, a flat file, a half-round rasp, and a flat rasp. What I like best about this tool is that both edges are "safe," or smooth. This makes the 4-in-hand rasp particularly useful when rounding-over tenons to fit into round-end mortises, like those cut by a router.

I also like how the shorter body fits nicely into my hand – and my shop apron pocket, too. My only use for this tool is light work, like fitting a joint or rounding-over tenons. If I have a lot of wood to remove or I'm working on a long or large surface, I'll pull out the appropriate standard-length file or rasp, since the short body of the 4-in-hand isadequate for this type of work.

I know quite a few woodworkers who enjoy using a rasp plane. Rasp planes are commonly referred to by their trade name, Surform (a Stanley registered trademark). Surforms come in several shapes and sizes, but all use the same cutting plate. This is a steel plate with rows of small teeth pressed into the surface. When dull the plate is discarded and a new one installed. The big advantage that this design offers over conventional rasps is that the teeth are a lot less likely to clog, since the waste can escape through the holes in the plate.

Surforms are intended for rough shaping, and they work well at this. I prefer other tools such as a draw knife or spokeshave, but my kids have always found Surforms very accessible. Each of them has spent away hours in the shop with me, reducing a square scrap into a convoluted object that when "finished" was proudly claimed to be rocket ship, doll, or doggy (although most ended up looking like hotdog buns).

Basic use
Naturally, if young kids can use one of these, Surforms are simple to operate. Hold the tool much as you would a jack plane or block plane, and use even pressure as you shape. You'll find that the tooth design allows you to cut both with and against the grain, leaving a rough surface. Once rough shaping is done, final smoothing is essential.

I was skeptical the first time I read the package on a Sandvik file I was considering purchasing. If the file was only half as good as they promised, it'd be worth the money. According to the package, here was a nifty product that would ideally replace both the files and the sandwich in my shop. Although this certainly has not happened, the Sandvik files that I've bought over the years have found a home in my tool cabinet.

Tiny holes
Sandvik files (and other abrasive tools, like their sanding block), are all faced with a special steel plate that has a series of holes punched in the surface to replicate a variety of abrasive grits. What makes this work is that the holes are punched in the metal with great accuracy. And unlike wallpaper, which wears quickly, the sanding plates last significantly longer. When they do wear out, you can purchase a replacement plate.

Basic use
Unlike standard files, Sandviks do not have to be pushed or folded in one direction. You can literally move these in any direction and they'll cut. This makes them particularly handy when working in tight quarters. The only secrets to using these are to let the sanding plate do the work, and to clean them often by rapping the tool against the side of your bench.

Several years ago, I was wandering around a woodworking show with a couple of dollars burning a hole in my pocket, when I saw a man demonstrating diamond hones. Seemed like a heck of an idea to me, so I bought a couple of flat pocket hones and a small set of diamond files and took them home to try. What a discovery. I use these little guys all the time for everything from tuning a plane to sharpening a router bit. I'm on my second set of paddles, and the files are still in good shape.

Diamond hones and files are basically pieces of high-grade plastic with crushed industrial-quality diamond particles bonded to the surface. Many shapes and sizes are available, and they typically come in fine, medium, and coarse grits. Without a doubt, I use the paddle-style hones the most often. There are two things that make these so great. First, since the abrasive is diamond, it lasts a long time. Second, their diminutive size allows them to access places other stones can not reach, such as the short bed of a block plane. Diamond hones and files can be used dry or else with water as a lubricant. Since I'm usually removing only a small amount of metal with one of these, a lubricant is unnecessary.

Source by Ted Willson

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