A jigsaw is a handheld power saw designed for cutting curves, openings, and irregular shapes in wood, plastic, and thin metal. Its narrow blade moves up and down rapidly, allowing the user to steer along a drawn path instead of cutting only straight lines. Jigsaws matter in workshops because they combine flexibility, portability, and relatively safe control compared with larger stationary saws.
They are often the first choice for making curved cuts, sink cutouts, and shaped project parts.
Key Facts
- Blade speed is often measured in strokes per minute, written as SPM.
- Cutting time can be estimated by t = L / v, where L is cut length and v is cutting speed.
- Blade tooth spacing is described by teeth per inch, written as TPI.
- Higher TPI blades usually give smoother cuts but remove material more slowly.
- Power can be estimated by P = E / t, where P is power, E is energy, and t is time.
- Orbital action makes the blade move slightly forward on the upstroke, increasing cutting speed but often making the cut rougher.
Vocabulary
- Jigsaw
- A portable power saw with a narrow reciprocating blade used to cut curves, shapes, and openings in materials.
- Reciprocating motion
- A repeated back and forth or up and down motion, such as the motion of a jigsaw blade.
- Kerf
- The slot or width of material removed by a saw blade during cutting.
- TPI
- Teeth per inch, a measurement of how closely spaced the teeth are on a saw blade.
- Orbital action
- A jigsaw setting that moves the blade in a small oval path to cut faster through some materials.
Common Mistakes to Avoid
- Using the wrong blade for the material, which can cause rough cuts, broken teeth, overheating, or unsafe binding.
- Forcing the jigsaw forward too quickly, which bends the blade and makes the cut wander away from the marked line.
- Starting a cut without clamping the workpiece, which lets the board vibrate and reduces accuracy and control.
- Cutting tight curves with a wide blade, which causes twisting and may snap the blade because the blade cannot turn sharply enough.
Practice Questions
- 1 A jigsaw cuts along a curved path that is 1.8 m long at an average cutting speed of 0.06 m/s. How long does the cut take?
- 2 A blade has 12 teeth per inch. How many teeth are along a 3.5 inch section of the blade?
- 3 You need to cut a smooth curved shape in thin plywood for a visible project part. Explain whether you would choose a high TPI or low TPI blade, and whether you would use strong orbital action.