Popular Woodworking 2002-10 № 130, страница 64

JOINTER

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Iarketing and misconceptions have led a lot of woodworkers to think that as long as they own a planer, they don't need a jointer. Nothing is farther from the truth. In fact, if you own a planer, you should definitely own a jointer.

While a planer is great for smoothing a board and reducing the thickness, you really need to start with a board that's flat and square to allow the planer to produce the results you want. And that's what jointers are all about.

SETUP & USE

Boards Aren't Flat?

In a woodworker's fantasy, every board bought from the lumber yard is perfectly flat and straight and at least 12" wide. Reality is

quite different. Wood is often crooked, bowed, twisted and cupped - see the drawing at right. If you're lucky that's only one board in your stack! To build something with those boards, they need some time on a jointer.

Start With Some Face Time

The face of a board (as opposed to the edge) is the first part to run over a jointer. But first let's make sure things are set up correctly.

If you've followed the jointer's directions, the outfeed table (the one to the left of the machine as you face it) and the knives are set at exactly the same height. In most cases, this is how the jointer arrives from the factory. For the first rough pass, the infeed table should be set about Vie" lower than the outfeed table.

BENCHTOP VS. STATIONARY Benchtop jointers are only recommended if your shop is small or you build only chairs or small boxes. Many are powered by universal motors, limiting their performance, and most have shorter beds than needed for adequately flattening boards. If you must go benchtop, go 6" and look for a decent motor size. Floor models range from 6" on up, but we don't recommend anything larger than a 12" jointer unless you're running a good-sized production shop. In general, an 8" jointer is a great option for most home woodworkers.A 6" will suffice but limits you somewhat. HAND WHEELS VS. LEVERS The infeed table on a jointer can be adjusted by either a hand wheel or a lever. Hand wheels are more precise, with each turn or quarter-turn producing a measurable height adjustment. While levers are more subjective, all jointers offer a scale to measure the height change, and it can be argued that jointers aren't used to remove exact amounts of material very often. Chalk it up to personal preference. KNIVES Knives will number two, three or four, depending on the size of the machine. Machines with two knives are exclusive to benchtop machines. Four blades will usually only occur on the largest of jointers. The more knives that cut the wood, the better the finish. So three is better than two. Stock jointer knives are

almost exclusively high-speed steel, and only production shops are likely to spend the money to replace them with carbide knives. This is more for durability, as steel knives still offer a better cut, but will dull and nick more easily Currently, few jointers use two-sided or disposable knives, but the trend that is sweeping planers may hit the jointers soon.

SETTING KNIVES Setting jointer knives is accomplished with either a magnetic knife-setting jig (using a magnet to lift the knife out of the cutterhead to the proper height), or jackscrew adjustment (lifting the knives to proper height by adjusting a set of jackscrews under the blade). Both methods are accurate, though we find jackscrews to be easier to adjust.

FENCES The longer the fence, the better. More importantly, the flatter the better. Due to internal stresses in cast iron, jointer fences can arrive warped or twisted. Whenever possible, check the fence prior to purchasing to make sure it is flat and straight. If you don't have the option to check it before it's delivered, make sure it is the first thing you do check. If it's not correct, contact the company and make arrangements to have it replaced. Fence movement also is important. It should slide easily across the table, and you should be able to move the fence to an angled setting with a minimum of fuss. Some jointers offer a rack-and-pinion mechanism for moving the fence, making it easier to quickly adjust the fence location.

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Popular Woodworking October 2002