One tool that always remains close to my workbench is the humble jig saw. It’s handy for quickly breaking down stock to a size that’s manageable on more precise machines, or for removing waste on curves or angles that would be difficult otherwise. For fine woodworkers and DIYers alike, it’s an easy and relatively inexpensive way to fill the gaps between other tools. However, it’s also an option that many shy away from for its undeniably rough results.
A VERTICAL RECIPROCATOR.
A jig saw is a vertically oriented reciprocating saw, which excels at cutting precise shapes, like a handheld scroll saw. Of course, a scroll saw is limited by what you can maneuver on its table. When a workpiece is too large to be easily controlled on a stationary tool, or when the arm of a band saw would interfere with the cut, the jig saw is the answer.
And yet, a number of features about your typical jig saw don’t lend themselves to fine woodwork. The orbital setting helps remove a lot of material, but not nicely. Most woodcutting jig saw blades also prioritize quick cuts over clean ones. Another issue jig saws face is deflection. Due to being fixed at only one end of its length, too much pressure on a blade can cause it to twist or curve during the cutting action.
Despite all this, there are ways to improve the quality of jig saw cuts. With the right blades and proper technique, it’s possible to bring the performance of a jig saw up to par with our other fine woodworking tools, without sacrificing what makes it useful in the first place.
JIG SAW BLADES
Like all tools, the jig saw’s usefulness is largely determined by its cutters. While there are a variety of blades for a variety of materials, I’ve limited the selection to a few useful for woodworking.
STRAIGHT & CURVE.
The first blades are the two upper ones from Festool: a straight cut and a curved cut. These are inexpensive and break down stock easily, but they aren’t very clean.
FINE CUT BLADES.
The “fine cut” type of blades are the first step toward a cleaner cut. If you look above, you’ll see they feature a slightly higher TPI than their straight and curved counterparts. Observe the tooth shape as well. Whereas the straight cut blade has long teeth with little hook angle to remove material fast, the fine cut blade is closer in shape to the curved cut blade, with a positive hook angle that cuts slower yet cleaner.
Blade length is also a factor. The fine cut from Diablo is 4" long, while the Festool option is 3". At face value, the Diablo blade may seem like a better choice. However, a longer blade means it’ll deflect easier during the cut — so, a shorter blade is often your best option until thicker stock requires a longer one.
SCROLL CUT BLADE.
Diablo’s scroll cut blade is an interesting choice. The first thing you may notice is the high TPI: twice that of the fine cut. Once again, I’d like to call attention to the teeth. Most jig saw blades are designed to cut on the upstroke so the cutting action pulls the workpiece into the baseplate. In contrast, this scroll cut blade’s teeth are triangular, with cutters along both edges so it cuts on both the up and down strokes.
As a result, this blade is excellent for cutting curves. It cuts slowly, but it offers a tighter turning radius and lower chance of chipout than other blades.
ULTRA FINE BLADE.
The final blade to mention is Diablo’s ultra fine blade. It has fewer teeth than the scroll cut (though more than the fine cut blades) and hook-shaped teeth like the curved and fine cut blades. Additionally, at the midpoint of the blade, the teeth switch direction. This means cutting occurs on both strokes, and that cuts are entering the face of the workpiece first, limiting chipout.
When cutting tight curves, control the saw by gripping directly above the blade and just barely guiding the rear.
Deflection occurs when too much force is applied during a curving cut, resulting in a rough and unwanted bevel. To avoid deflection on curves, apply minimal pressure while cutting, allowing the teeth to do the work.
JIG SAW TECHNIQUES
Before jumping into a couple techniques I use, there’s one thing to mention. Take a look at your jig saw. Does it have an orbital setting? This presses the blade into the cut on the upstroke and pulls it back on the downstroke. This action improves cutting speed — great for rough, construction work, not so great for fine woodworking.
HAND POSITIONING.
One of the biggest annoyances on a jig saw is cutting a curve only to find you’ve somehow made a bevel. This is a result of deflection, and it’s illustrated on the previous page. If you push the saw into the cut faster than the teeth can remove the material, or you attempt a tighter turn than the blade’s width allows, you end up pushing the flat of the blade against the sidewall of the kerf. This causes the unsupported end of the blade to flex.
My fix is to adjust my hand placement. I control the saw with one hand directly over the blade, while my other simply rests on the back to help control the turns. This limits how much pressure I can apply and gives me greater control during the turn.
ZERO-CLEARANCE BASEPLATE.
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| A zero-clearance baseplate can be created for a jig saw by cutting a piece of acrylic to match the size of the baseplate, creating a kerf for the blade, and attaching it with double-sided tape. Casted acrylic (like Plexiglass) is preferable over extruded acrylic as it’s clearer, providing better visibility. |
One final piece of advice I can offer is the zero-clearance baseplate you see above. Just like any other, it’s meant to support the wood fibers directly beside the cut, preventing them from chipping or tearing. I use this when cutting something with a face veneer, as those can be particularly vulnerable to jig saws.
