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From the pages of Power Tools
Jigsaws
"With its narrow blade that cycles up and down like a carousel horse, a jigsaw can cut all kinds of curves and circles -- square or beveled -- as well as scroll cuts fancy enough for any gingerbread decoration." So writes Sandor Nagyszalancy in his book Power Tools. In this excerpt from Part 1, Sandor examines a variety of jigsaws and their features.
The variable speed and orbital-blade action found on most jigsaws make them extremely versatile tools capable of cutting cleanly and accurately a wide range of materials, including wood, metal, plastics, cardboard, and leather. One particularly handy jigsaw trick is plunge cutting into a surface to start a cut in the middle of a panel -- say, to saw out an electrical outlet in a wall or to cut out a countertop for a kitchen sink. To add to its versatility, you can pick a jigsaw that's powered by household current, batteries, or compressed air. Or you can choose a bayonet saw that's compact and powerful enough to tackle the most demanding carpentry chores.
Types of jigsaws
Corded jigsaws -- The modern corded jigsaw is a sophisticated curve-cutting machine with a multitude of features that enable it to accomplish all kinds of cuts in all kinds of materials. The most powerful corded jigsaws can cut wood up to 2-3/4 in. thick, 3/4-in.-thick aluminum, and even 1/4-in.-thick mild steel. The biggest difference among corded saws is their body/grip style. Barrel-grip saws, preferred by Europeans, such as the Bosch 1584AVS and the Fein Aste 638, are held by wrapping one hand around the motor housing; top-gripped D-handled saws, such as the DeWalt DW321 and the Porter-Cable 9543, are preferred by American craftsmen.
Cordless jigsaws -- Snip the power cord from a traditional jigsaw, fit a battery, and you have a truly portable saw. Now you can cut rounded shingles for your daughter's treehouse or cut a shapely curve on your sailboat's transom without long extension cords or the worry of electrocution. Although they're less powerful than corded saws and need recharging, cordless saws, like the Makita 4332DZ, pack some impressive features. The 14.4-volt Makita sports variable speed, a tilting baseplate, a blade-orbit selector, and an electronic brake that stops the blade the instant the trigger is released.
Pneumatic jigsaws -- While air tools are fairly common among portable sanders, it's a fairly new concept among jigsaws. Connected to a good-sized compressor, the Bosch 7561 118 is just as versatile and cuts just as powerfully as similarly featured corded models but weighs about a third less. Lacking a cord also makes it safe to use in wet or damp places, where running an AC-powered tool would be unsafe. The pneumatic Bosch is activated by a paddle-trigger air control beneath its narrow barrel-grip body.
Bayonet saws -- Developed in the mid 1950s by Porter-Cable, the bayonet saw is a slightly different animal than the other jigsaws featured in this chapter. The low-profile Porter-Cable 548 saw uses a worm gear to transfer power to the blade-reciprocating mechanism. The saw's sturdy, nontilting base and large 7/16-in. blade orbit make it great for square cuts in metals, plastics, thinner woods, and laminates.
Features
Quick-release blade change -- To make blade swapping quicker and less tedious, the best jigsaws incorporate some kind of quick-release blade-changing device, which does not require any tools to operate. To change blades on models like the Skil 4470 and Porter-Cable 9543, you simply press or pull a lever or flange located on the end of the blade carrier itself.
The blade-changing mechanism is more integral on jigsaws like the Bosch 1584AVS and DeWalt DW321; the top handle on both saws rotates to lock or unlock the shanked blade below. Even though the Fein Aste 638 jigsaw doesn't have tool-free blade change, it offers a great time-saving feature: The saw's top handle unscrews to reveal an Allen wrench that is used to lock or loosen the blade.
Blade action and speed control -- Inexpensive jigsaws that simply thrust their blades up and down get the job done, but they don't cut aggressively and they wear their blades down quickly. Premium jigsaws offer varying degrees of blade action: straight line or orbital. Orbital action uses an oscillating mechanism to move the blade in a slight circular motion as it reciprocates. The blade moves forward on the up stroke (the direction the teeth cut in), helping it to cut more quickly and aggressively, then moves back on the return stroke, keeping the teeth clear of wear. Since different kinds of cuts in different types of materials require varying degrees of orbit, jigsaws such as the Freud FJ85 have a selection lever to let you choose the amount of orbit: more for straight, super-fast cuts or energetic cuts in porous materials; less for curved cuts, tight scroll work, or slower cuts in dense materials like metals.
ELECTRONIC VARIABLE SPEED: For a jigsaw to wear its crown of versatility, it must cut many different materials with the same alacrity. Variable speed is as important to that goal as choosing the right kind of blade. Deep cuts in dense hardwoods require high speed, while hard steel demands much slower blade reciprocations. The Fein Aste 638's variable-speed control is at the end of its motor housing, while the Bosch 1581AVS has a dial mounted on the trigger itself.
Bases -- While a jigsaw's blade spends much of its time set square to its base, most saws allow the saw to be tilted for bevel cuts. Typically, loosening a single screw allows the base to tilt up to 45° in either direction. While many saws provide an on-board Allen wrench for base adjustments, the DeWalt DW321 and Porter-Cable 9543 do one better: A built-in lever loosens and tightens the base to allow tilting. The bases on these saws slide back and forth and lock at 45° or 90°, eliminating the need for a square or protractor to set these commonly used angles. And by sliding the bases backward and locking them, you can saw right up to a wall or other vertical surface -- handy when working inside a cabinet or closet. Many premium saws also have a smooth plastic cover or insert on the metal baseplate that won't scratch delicate surfaces, such as veneers or plastic laminates.
ANTISPLINTERING INSERT: Although many jigsaw owners use their saws to cut metal, plastic, rubber, leather, and even paper, most use their saws to cut wood. Because a jigsaw cuts on the up stroke, it has a tendency to tear out wood fibers on the top side of the cut. This is bad because it obscures the line of cut and results in a rough, splintery edge. Therefore, better-quality jigsaws like the Festo PS2 E-Plus have a slot at the front of the base for mounting an antisplintering insert. Made from plastic, the removable, replaceable insert fits close to the cutting edge of the blade, thus supporting the wood fibers at the point of cut and significantly reducing tearout.
Blade guides -- When it comes to cutting thick materials without twisting or bending, the narrow reciprocating blade of a jigsaw can use all the help it can get. Many models offer help in the form of a blade guide: a grooved disk that supports the back edge of the blade. This keeps the blade running straight and helps it resist deflection, which improves the accuracy of the cut and reduces blade bending and breakage. On orbital jigsaws like the Makita 4332DZ, the blade guide serves a double duty: The arm to which the guide disk is mounted swivels back and forth, thus initiating the orbital action.
Accessories
Blades -- The failing of many early jigsaws were cheap blades that compromised the saws' cutting performance. Fortunately, modern jigsaw blades employ as much advanced technology as the jigsaws themselves. The shape, size, and spacing of teeth on a blade affect its performance as well as the material from which it's made. Good general-purpose wood-cutting blades, such as the Metabo and Bosch blades, have precisely machined taper ground teeth, while the DeWalt cobalt-steel blade has a reinforced tooth design. Bosch's savage-looking Progressor blade features a variable tooth size, for aggressive cutting and less splintering. The Bosch bimetal blade has hardened carbon-steel teeth bonded to a high-speed-steel back. The durable teeth stay sharp while the flexible blade body resists breakage, making bimetal blades ideal for demanding tasks.
Stationary table -- Routers aren't the only portable tools you can mount in a table. When inverted and attached to a stationary table, a jigsaw is very useful for sawing small or delicate workpieces. Made from cast aluminum, the Bosch stationary jigsaw table conveniently clamps to the edge of a table or benchtop. A pair of cleats and a locking plate secure the jigsaw to the underside of the table but allow quick removal when it's needed for portable duties.
Edge guide and circle jig -- Because they are light and portable, jigsaws excel at freehand cutting of curvy parts. Still, there are times when a jigsaw is the best tool for making a straight cut. To assure an even rip or square crosscut, fit the saw with an edge guide. Like other jigsaws, the edge guide on the Metabo STE105 Plus attaches near the front of the baseplate, adjusting in or out to set the distance between the fence and the blade. By flipping the edge guide over and mounting a pivot knob, the Metabo's guide serves double duty as a circle jig.
Dust control -- All the jigsaws and other electric portables with built-in dust collection have spawned a whole generation of sophisticated shop vacuums designed to work in tandem with power tools. The German company Festo offers an entire line of compact shop vacuums, with natty green-striped hoses that connect directly to their portables. The fine dust-trapping Festo CT 33 E vacuum has a built-in electrical outlet for the power tool and circuitry that turns the vacuum on and off automatically in concert with the tool.
DUST BLOWING: Getting chips and dust out of the way not only makes using a jigsaw a cleaner proposition -- it's essential if you're trying to see the line you're cutting! Early jigsaws often kept the sight line clear with a built-in dust blower that piped a small stream of air in front of the blade. Nowadays, premium jigsaws have built-in dust collection, which pulls air from behind the blade to draw vision-obscuring dust away from the line of cut. To enhance collection and to block chips from flying into your eyes, the Metabo STE105 Plus encloses the blade in a transparent, removable plastic guard. Chips are drawn through the base of the saw to a vacuum hose, which attaches to a port at the rear of the motor housing.
Sandor Nagyszalancy, a former senior editor of Fine Woodworking, is a professional furniture maker, designer, and tool expert. His other books include The Art of Fine Tools, Setting Up Shop, Woodshop Jigs and Fixtures, Fixing and Avoiding Woodworking Mistakes, Woodshop Dust Control, and The Wood Sanding Book.
Photos: Sandor Nagyszalancy; Drawing: Mark Sant'Angelo
Excerpted from Power Tools, pp. 42-56
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