Reciprocating Saw Blades: TPI, Length and Which to Use

Match the reciprocating saw blade to the material. Use about 3 to 6 TPI for wood and pruning, 6 to 10 TPI for wood with nails, about 14 TPI for metal 1/8 to 1/4 in (3 to 6 mm) thick, and 18 to 24 TPI for thin metal and tube. Bi-metal blades suit most jobs, and carbide or carbide-grit blades suit cast iron, masonry and tile.

Reciprocating saw blades at a glance

Job	Typical TPI	Blade type	Typical length
Green wood, pruning	3 to 6	Wide-tooth, often curved	6 to 12 in
Rough wood and framing	3 to 6	Bi-metal or high-carbon	6 to 9 in
Demolition (wood with nails)	6 to 10	Bi-metal or carbide-tipped	6 to 9 in
Thick metal, pipe and bar	10 to 14	Bi-metal	6 to 9 in
Thin metal, sheet and tube	18 to 24	Bi-metal	4 to 6 in
Cast iron, tile, masonry	None	Carbide-grit or carbide-tipped	6 to 9 in

Makers’ packaging gives their own ranges, so follow the label if it differs.

How TPI changes the cut

Low TPI means fewer, larger teeth and big gullets between them. Those clear wood chips quickly and cut fast, but they grab and snag in thin metal. High TPI means more, smaller teeth that take small bites, which suits thin metal but clogs and burns in wood. The thickness of metal sets the choice: thin sheet and tube need fine teeth, thick bar and pipe tolerate coarser ones.

Bi-metal, carbon steel and carbide

• Bi-metal blades have hardened high-speed steel teeth on a flexible spring-steel body. They are the standard for wood, nails and metal, and they last far longer than plain carbon steel blades in metal; see best saw for cutting metal.
• High-carbon steel blades are cheap and flexible, but they dull fast in metal. They are fine for wood and pruning.
• Carbide-tipped and carbide-grit blades cut cast iron, tile, brick and fiber cement, and last longer in demolition. They cost more and chip if misused.

Blade length and thickness

A longer blade reaches deeper but flexes more. Pick a length that clears the thickness of the cut by an inch or two, and use a shorter blade when you can for a straighter cut. Thicker blades flex less and resist bending in pipe and heavy work, and thin blades turn more easily for curves. Blades with a universal shank fit most reciprocating saws.

How to use a reciprocating saw

1. Clamp the work if it is loose, and check what is behind it. A blade that goes through can hit pipes, wiring or people.
2. Rest the saw’s shoe firmly against the work. This reduces vibration and blade breakage.
3. Start the blade moving before it touches the material, and let it cut. Don’t force it.
4. In metal, use a slower speed and a few drops of cutting oil. In wood, run at full speed.
5. Use orbital action, if the saw has it, for fast rough wood cuts, and turn it off for metal and clean cuts.
6. Support the cut-off piece so it does not pinch the blade.

For hand-powered alternatives in metal, see hacksaw blade TPI, and for curves and sheet, see jigsaw blades. A comparison of blade types for circular saws is in saw blade types.

Safety

Wear safety glasses and gloves, keep both hands on the saw and clear of the blade, and unplug the saw or remove the battery before changing a blade. Cut metal that is clamped, and let hot blades cool before touching them.