How to use a jigsaw to cut better
While you may not need it every day, there are some jobs you’ll do better than ever if you know how to use a jigsaw to cut.
Jigsaws are easy to use, and, whether corded or cordless, today’s models are powerful and versatile. Power and features vary so much that you can spend less than $30 for a tool that’ll just about get the job done or more than 10 times that for one that sings. Most professionals will want a fully featured D handle top-grip jigsaw and a smaller barrel-grip model.
If you want to use a jigsaw to cut, a corded jigsaw needs a reasonable amount of power so you’ll be looking for one with a motor that draws 6 or more amps. However, with the high-power batteries available today, there’s little performance difference between corded and cordless jigsaws.
And for really fast cutting, the saw should feature an adjustable orbital action that will help the blade bite into the workpiece.
What can it do? You can use a jigsaw to cut soft or hard wood, aluminum, copper, and steel, ceramic, acrylic and fiberglass. The material determines the blade and the jigsaw provides the power and driving force.
The jigsaw should fit your hand comfortably and may have a second pad where the other hand can push down directly over the blade to aid in keeping the foot on the job and avoid chatter as the blade advances and returns – it cuts on the upstroke drawing the saw footplate to the work. The trigger, which may also be the speed control, can be a single finger switch but most professional users who saw a lot will prefer the two-finger trigger.
Speed on the higher-end jigsaws is controlled by a rotary switch that may be on the trigger or on the body of the tool. There will also be a switch to allow you to select the orbital mode. At least one jigsaw model has an automatic load-sensing control. Once the speed is set, it remains constant during use.
Other features make it easier to follow marked lines for the cut. LED lighting, positioned so it doesn’t shadow the blade or markings is handy. One jigsaw – a very expensive, high-end tool – comes with four LEDs arranged around the blade that can be set to strobe in time with the jigsaw frequency.
As a further aid in following the lines, the motor exhaust is directed onto the blade to blow away sawdust that otherwise obscures the markings on the job. This feature can be disabled when the dust collection accessory is used because the vacuum pulls the sawdust back from the cut.
Very desirable are toolless adjustment for the footplate and toolless blade changing. The footplate on most jigsaws can be angled for a miter cut of up to 45 degrees and many have detents for the most common angle cuts.
This can be limiting if you need a different angle. Jigsaws come with different base plates for different surfaces. At least it should have a shoe cover that can be used on surfaces that could be marred by the base plate.
The toolless blade change is almost universal on professional jigsaws, though each manufacturer has a different lever system for clamping the blade in place. Some are very easy to use, others are less so, so check to be sure it’s something you like.
The best designs actually eject the blade with a light spring so you don’t have to touch them. This is a good thing because anyone who has ever used a jigsaw has grabbed a hot blade at some time or another and discovered how very hot they can get, especially when they lose their sharpness. Always disconnect the cord or the battery when changing blades.
The jigsaw should also have a blade support adjustment. This is a roller that supports the back side of the blade and on top-end models can be adjusted to apply light pressure onto the blade shank during use.
How to use a jigsaw to cut
The jigsaw is the tool of choice for following any cut line that is not straight. However, using a clamped straight edge, the jigsaw can make a very acceptable straight cut as well.
New users often make the mistake of forcing the jigsaw into the cut. The trick is to let the saw do the work while you guide it with light pressure. That way, the cut is cleaner, there’s less breakout of material and the job goes easier. If you find you need to push harder to progress through the material, it’s likely time for a fresh blade.
Jigsaws are often used to cut out a section of a board or sheet. This could be the cutout for a sink in a countertop or a pass-through for plumbing. This is where quality tools and blades count, as they create openings at perfect right angles to the surface. Cheap products often allow the blade to deflect especially in a curving cut, creating an unsatisfactory off-angle result.
For internal cuts like these, drill a hole the blade can start in. Drill it close inside the marked line.
For a rectangular cutout, such as for an electrical outlet, drill four holes, one at each corner, to allow the blade to change direction. Then finish the corners individually finished using the jigsaw.
Because the blade cuts on the upstroke, there is plenty of opportunity for breakout of material on the upper surface of the job. This is aggravated by heavy orbital action and aggressive teeth pitch on the blade.
One way to avoid this is to cut with the back side uppermost, but there’s plenty of opportunity to cut in the wrong place when inverting a counter, for example.
To protect against break out, the best jigsaws have splinter guard inserts that fit close to the blade. One model has blank guards that are inserted in to the guides as the jigsaw is running for the closest possible fit to the blade.
With zero orbital motion and slow speed, you can use a jigsaw to cut laminate with zero chipping.
There are also reverse tooth blades that cut on the down stroke. These can be used on material that is likely to chip, but require additional downward pressure on the saw to keep the foot plate in contact with the surface.
Another handy feature is blade storage. Some jigsaw models provide storage for several blades on a magnetic strip or in a small compartment.
Blade choices
Jigsaw blades are meant to match the work. They are disposable and, because they are supported only in the clamp, prone to breakage, especially when overloaded or overheated. Because blade changes are common, a toolless blade clamp system is a great feature.
Blades have two shank types: the T-shank and the older U-shank. T-shanks are for toolless clamps while, generally, the U-shank will be retained by a screw, most often an Allen screw.
Blades are made to use on softwood, hardwood, plastic, aluminum, copper, ferrous metal, wood with embedded nails, ceramics, glass, concrete, plaster, marble, drywall, fiberglass − even thick leather. In general, the harder the material, the harder the blade. The downside? As blades become harder they also become more brittle.
High-carbon steel blades are flexible and cut softer materials but they are also the weakest and wear out fastest. Still they cost little and cut wood very well, so they are often installed in the tool when you get it.
High-speed steel (HSS) blades are for tougher cutting tasks and can last up to 10 times as long as a cheaper blade. Bi-metal blades will cut through wood with embedded nails. For specialty tasks like ceramics or stucco, use tungsten carbide-tipped blades. They’re expensive and slow but also the best blade for the job.
Blades are specified by the teeth per inch (tpi) and the aggressiveness of the tooth design. Generally, the more jagged they look, the faster but rougher the cut. Metal cutting blades have fine teeth set is a wavy pattern. Wider blades are for gentle curves and straight lines. Tighter curves are best handled with a narrow blade and the tightest radius curves can be made with specialty blades that have teeth on both sides of the narrow blade.
Surprisingly clean cuts are possible with a jigsaw and the correct blade, and manufacturers generally mark the blades for the material they are designed to cut. Bosch even color codes the blades according to task. Experience (and broken blades) will quickly reveal which type will work best on your job.
−By Steve Sturgess, stevesturgess.com