Reciprocating Saw Blade Guide: Which Blade Cuts What

How TPI Determines What You Cut

TPI is the single most important number on a recip saw blade. Low TPI (3 to 6) cuts fast and rough. The big teeth take aggressive bites, clear chips quickly, and rip through wood, nail-embedded lumber, and tree limbs. High TPI (14 to 24) cuts slower and smoother. The fine teeth handle metal, thin-wall pipe, and sheet goods without snagging or tearing.

The general rule: at least 3 teeth should be in contact with the material at all times. On a 2x4 (1-1/2 inches thick), a 6 TPI blade has 9 teeth engaged, which is plenty. On 1/16-inch sheet metal, that same 6 TPI blade has less than 1 tooth in contact, which grabs, vibrates, and destroys the cut edge. You would need 18 to 24 TPI for that material.

This 3-tooth rule is the fastest way to pick the right blade in the aisle. Estimate the material thickness, multiply by the TPI, and confirm you get at least 3. If the number is less than 3, move to a higher TPI. If it is well above 10, you can drop to a lower TPI for faster cutting speed.

Wood Blades

Standard wood blades are 6 to 9 inches long, 5 to 6 TPI, and made from HCS (high-carbon steel). They are cheap ($2 to $4 each), cut fast in framing lumber, sheathing, and dimensional stock, and are easy to find at any hardware store. The downside: they dull quickly on nails and screws. For clean wood without fasteners (pruning, rough carpentry, cutting pallets apart), HCS blades are the practical choice.

For demolition work where the wood might contain nails, screws, or staples, step up to a bi-metal blade. Bi-metal blades have HSS (high-speed steel) teeth welded to a flexible carbon steel body. The HSS teeth survive nail strikes that would destroy HCS teeth. Demolition bi-metal blades in 6 to 10 TPI handle everything you find inside a wall during a remodel: wood framing, nails, drywall, plywood sheathing, and occasional metal strapping.

For general remodeling, keep a 5-pack of 9-inch, 6 TPI bi-metal blades on hand. They cover the majority of demolition cuts. A 5-pack from DeWalt, Milwaukee, or Diablo runs $12 to $20. At that price, treat them as consumables and replace them at the first sign of dullness rather than pushing through with a blade that is generating heat instead of cutting.

Metal Blades

Metal cutting blades run 14 to 24 TPI and are always bi-metal or carbide-tipped. For mild steel, copper pipe, and aluminum, 18 TPI bi-metal works well. For cast iron, stainless steel, and hardened steel, carbide-tipped blades last 10 to 20 times longer but cost $8 to $15 each compared to $3 to $5 for bi-metal.

Blade length matters more for metal than for wood. Use the shortest blade that reaches through the material. Long blades flex under the cutting pressure and deflect, giving you a curved cut instead of a straight one. For pipe, the blade should extend 2 to 3 inches past the pipe diameter. For flat stock, match the blade length to the thickness plus an inch. A 6-inch blade through 3-inch pipe gives you the right amount of rigidity.

Diablo, Lennox, and Milwaukee Torch blades are the names recommended consistently by plumbers and HVAC techs for daily metal cutting. The Milwaukee 48-00-5193 TORCH carbide-tipped blade ($12 to $15 for a 5-pack) is a favorite for cutting cast iron soil pipe, which destroys bi-metal blades in a few cuts.

Specialty Blades

Pruning blades (3 to 5 TPI, aggressive tooth set) cut green wood and branches faster than standard wood blades because the wide tooth set clears wet chips that would clog a standard blade. Tree service pros keep a stack of these. For homeowners, a pruning blade turns a recip saw into a surprisingly effective limb trimmer for branches up to 6 inches in diameter. A 12-inch pruning blade from any major brand costs $5 to $8 and handles dozens of cuts.

Carbide-grit blades have no teeth at all. Instead, a tungsten carbide coating on the edge grinds through cement board, fiberglass, brick, and tile. They are slow compared to toothed blades, but they cut materials that would destroy any conventional blade. For cutting a hole in a cement board shower surround or trimming fiber-cement siding, a carbide-grit blade is the only recip option that works.

Long-reach blades (12 to 16 inches) handle deep cuts in walls, timbers, and posts where standard 6 to 9-inch blades cannot reach. The tradeoff is more blade flex, which means less control over the cut path. Guide the blade carefully, let the weight of the saw do the work, and do not force the cut. These blades are common in demolition and timber framing.

Blade Material Comparison

Three blade materials cover the range from budget to professional:

• HCS (high-carbon steel) — cheapest, $1 to $3 per blade. Good for clean wood only. Dulls on nails and does not cut metal. Fine for pruning and rough carpentry with no embedded fasteners.
• Bi-metal (BIM) — mid-range, $3 to $6 per blade. HSS teeth on a flexible body. Handles wood with nails, mild steel, and general demolition. The workhorse blade for most users.
• Carbide-tipped (CT) — premium, $8 to $15 per blade. Carbide teeth last 10 to 20 times longer than bi-metal in metal cutting. Worth the cost for cast iron, stainless, and high-volume work. Overkill for clean wood.

For most homeowners and remodelers, a mixed pack of bi-metal blades (6 TPI for wood/demo, 14 TPI for metal) covers 90% of situations. Carbide-tipped blades are worth stocking if you regularly cut cast iron drain pipe, stainless exhaust, or hardened fasteners.

Getting the Most Life from a Blade

Let the blade do the cutting. Pushing hard does not speed things up. It heats the blade, dulls the teeth, and increases the chance of blade breakage. Keep the shoe (baseplate) pressed firmly against the workpiece to minimize vibration and blade whip.

Match your speed setting to the material. Full speed for wood. Medium speed for metal, because the slower stroke reduces heat buildup that destroys teeth. Most modern recip saws have variable speed triggers. Use them. Full speed through metal is the fastest way to ruin a blade.

When a blade stops cutting and you find yourself compensating with pressure, it is done. Swap it out. A dull blade generates heat instead of cuts, and the heat can damage the workpiece, warp the blade, and strain the saw's motor. Blades are consumables. Keeping a few spares in the tool bag is cheaper than pushing a dull blade until it breaks.

Frequently Asked Questions

Can one blade cut both wood and metal?

Demolition blades (8 to 10 TPI bi-metal) are the best all-around compromise. They handle nail-embedded wood, light metal, and mixed materials. They will not cut clean wood as fast as a 6 TPI wood blade, and they will not cut thick metal as cleanly as an 18 TPI metal blade. But for demo work where you are cutting through whatever is in the wall, they are the standard choice.

How many cuts does a recip saw blade last?

It depends heavily on the material. A bi-metal demo blade lasts 20 to 50 cuts through 2x4 with nails. A carbide-tipped blade in the same application might last 200+. In clean wood, an HCS blade handles 100+ cuts before dulling noticeably. Track how the blade is performing rather than counting cuts.

Do all recip saw blades fit all recip saws?

Almost all. Modern reciprocating saws use a universal 1/2-inch tang (the part that slots into the blade clamp). Blades from any major brand fit any modern saw. Very old saws from the 1980s or earlier might use a proprietary tang. Check your saw's clamp before buying in bulk.

Are carbide-tipped blades worth the extra cost?

For metal cutting, absolutely. A $12 carbide blade that makes 200 cuts costs less per cut than a $4 bi-metal blade that makes 30. The math is straightforward. For wood-only cutting where nails are not present, carbide is not necessary. Save the premium blades for the hard materials where they pay for themselves in blade changes saved.

Related Reading

• Best Reciprocating Saws Compared
• Reciprocating Saw Guide
• What Is TPI?
• Angle Grinder Disc Guide
• New Homeowner's Tool Guide