Popular Woodworking 2000-06 № 115, страница 35
A SIMPLE FILING JIG One of the most critical steps to successfully sharpening a scraper is to first establish an absolutely flat, square edge. For years, I've used a simple shop-made file holder for this.The holder is just a short length of stock with a groove cut in it to accept a mill file.To use the holder, slip a file in the groove (if necessary, insert a paper shim to grip the file and keep it from shifting in the groove).Then with the scraper clamped in a vise, place the face of the wood against the face of the scraper and file in one direction only, lifting the file at the end of the pass. File until you can see a uniformly fresh edge on the scraper. The first step to sharpening is to file a flat, square edge. Clamp the scraper in a vise and use a shop-made holder to ensure a square cut. To create a strong burr, first "draw"the burr to consolidate the metal on the edge. Lay the scraper flat and run the burnisher along the edge while held at a 15-degree angle. Go back and forth several times. rious at first, but all you're doing is making it easier to roll a burr. At the same time, you're hardening the steel so the burr will last longer. To draw the edge, lay the scraper flat on the edge of your bench and draw the burnisher (held at about a 15-degree angle) along its edge. A drop of oil, firm pressure and a handful of strokes will do the job. Repeat this on all four edges. Next, to roll the burr on each edge, start by clamping the scraper in a vise. Now hold the burnisher at about a 15-degree angle and run it along the edge of the scraper. Firm, steady pressure works best -don't go overboard here. If you want a fine burr, stop after two or three strokes. Keep Be sure to cock the scraper at an angle to the grain as you pull it or push it. Remove any burrs you created when filing the scraper by placing the tool face down on a sharpening stone and rubbing in a circular motion.
going for a heavier burr. Stop often and check the burr by sliding your thumb gently up the face of the scraper and over the edge. With experience, you'll soon be able to "gauge" the size of the burr. Using a Scraper I've often seen someone pick up a freshly sharpened scraper and not be able to get a decent shaving. Why? Rolling a burr isn't an exact science - every time you burnish it the angle changes. This means you have to "find" the best angle to hold the scraper. Quite often, all they have to do to get great shavings is to tilt the scraper one way or the other. It really is trial and error. Push or Pull? Ah, the great debate - whether tis' nobler to push or pull a scraper. My answer: whatever works best for you. I tend With the scraper clamped in a vise and holding the burnisher at a 15-degree angle, press firmly down and run it along the edge. Depending on pressure and the hardness of the metal, two to four passes will usually get the job done. to push a scraper because it allows me to get more muscle behind it. For delicate work, I often switch to pulling as I feel it gives me finer control and allows better "feedback" from the wood. Regardless of whether you decide to push or pull, you'll have better luck if you flex the scraper. This does a couple things: it keeps the corners from digging into the surface, and it concentrates the scraping action on a smaller section of work. Another trick I often use is to skew the scraper slightly. This prevents it from following uneven surfaces (like planer marks) and quickly levels high points. Scraping can be hard work, and if you need to remove a lot of material, you'll find the scraper may get too hot to handle -the friction and heat it creates will quickly spread to your fingers. Although I've seen lots of tips on preventing scorched fingers - everything from finger protectors to refrigerator magnets - I offer an alternative. If you have to remove a lot of material, a scraper isn't the best tool for the job. Set it aside and pull out a hand plane. Once the bulk of the material is removed, generate some of those wispy shavings with your new favorite tool. PW |
