Popular Woodworking 2008-10 № 171, страница 38
to as scribing, and t he lines are referred to as senbe lines. Some layout toolsscnbciheirown lines. Others rcquireaseparatetool.onethat is referred toasa striking knife.
Tools lhal Scribe
A striking knife has a flat-backed, usually V-shaped blade with a suitable handle. The critical feature isthe Wade. It isground on only-one side rather than on both, as your pocket knife would be. If rather than Hat the blade is ground on both sides like a knife, the scribe line would be offset by up to half the thickness of the striking knifes blade.
So in use. the flat side of the blade is run against the layout tool. The tip of the blade is often V-shaped toallow the knife to he used in either direction and by left- and nght-handed woodworkers.
It istmportanuokeepyourstrlkingkntfe sharp, as a dull knife will crush and tear wood fibers, rather than scribe cleanly. A scribe line made with a striking knife can be faint, but readily visible if you work with light coming
slightly from the side. Its shadow makes the line easy to see.
If you haw t rouble seeing t he scribe line, run a pencil light ly along it to leave behind a little graphite. It does not make the senbe line wider like a pencil line, just easier to see.
Layout lines are usually- very fine and are easily planed, scraped or sanded away. As an aside, woodworkers in the past did not usually bother. One feature that helps determine whether a piece of furniture isagenuine antique arc the layout lines. I like these layout lines because through them the long-dead furniture maker is telling me how he worked.
Begin with the Basics Most layout tools will require that you first establish a st raight and t rue edge on a piece of wood. Forthat reason, the straightedge isthe most basic layout tool. A straightedge isdtffer-ent from a ruler or a yardstick. Its purpose it to provide what its name implies - a straight edge. Whilesomestraightedgesarcgraduated for use in measuring, their primary purpose is toguarantee a straight line. You can measure with a ruler, but a rukr does not necessarily provide the precision you want when check-inga straight edge or a flat surface.
Striking knife, louse J striking knife, hold the tlat side firmly against your guide and draw the knife toward you to scribe a bne.
A si raightedge is usually made of steel and is thus much heavier than a ruler. They also cost a lot more. Because straightedges have a lot more uses in a shop than just making straight lines,iheyareworththeexpense. You will not often need one more than 24" long
Sometimes in woodworking you have to saw or plane toa line longer than you can trace. Wlule it may- seem an unlikely candidate for inclusion wit h other layout tools, long layout lines are best made with a chalk line. This technique isancient. Astnngiscovered with a very fine colored powder (nowadays either red or blue chalk)and when drawn tight and snapped. I he si ring leaves a perfect ly- st raight line of powder for you to follow.
All you need todo is locate the point at one end of the line you wish to make and a corresponding point at the other end. Thcchalk line has a hooked tab that will secure it over the end of a board (but a third hand can also be useful). The tab has a tnangular opening in it so you can make sure the tab is perfectly aligned with your beginning mark. Simply be sure the mark is in the point of the t riangk-
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