Reciprocating Saw Blade Types: Guide to TPI, Material, and Application

Reciprocating saw blades are one of the most commonly used cutting tools in construction, demolition, plumbing, and renovation projects. From tearing down wooden structures and metal pipes to cutting masonry, composite materials, and other specialty materials, the success of this powerful tool depends heavily on one key component—the reciprocating saw blade itself.

Using the wrong reciprocating saw blade can slow down cutting, cause excessive vibration, wear out the blade prematurely, or even pose a safety risk to the operator.

Understanding the different types of reciprocating saw blades and the different blade designs made for specific materials can help you choose the right blade for each job, resulting in faster, cleaner cuts and longer blade life.

Reciprocating Blade Construction

The material used in the teeth determines the blade’s flexibility, durability, and heat resistance.

• High Carbon Steel (HCS): The most flexible and affordable. Best for soft wood and plastics.
• Bi-Metal (BIM): The industry standard for demolition. It fuses a flexible HCS body with a hard High-Speed Steel (HSS) edge. This allows the blade to bend without snapping while cutting through wood with nails.
• Carbide-Tipped: These feature individual carbide teeth brazed to the body. They are the only choice for thick stainless steel and high-strength alloys.
• Carbide/Diamond Grit: Instead of teeth, these use abrasive particles to grind through brittle materials like tile, cast iron, and masonry.

Mastering TPI and the "Three-Tooth Rule"

Teeth Per Inch (TPI) is the most critical factor in cut quality and speed.

• Low TPI (3–8): Large teeth and deep gullets. Used for Wood and Pruning.
• High TPI (14–24): Small, fine teeth. Used for Metal and PVC.

Important Note:

When cutting metal, you must adhere to the Three-Tooth Rule: At any given moment, at least three teeth must be in contact with the material's thickness. If the teeth are too large (Low TPI), they will "straddle" the thin metal wall, causing the blade to snag, vibrate violently, and eventually strip the teeth off the blade.

Preventing Blade Failure: Heat and Speed

Heat is the main reason for the premature failure of the blades. When a blade gets too hot, the steel undergoes a process called "annealing," where it loses its hardness (often indicated by the steel turning a blue or rainbow color).

To maximize blade life, you must manage your saw's speed. Wood requires high speed to clear large chips effectively. However, Metal and Masonry require a slower speed. Running the saw at full trigger-pull through a stainless steel pipe creates extreme friction that will dull even a carbide blade in seconds. If you see smoke or the blade turning blue, you are running too fast. In heavy metal applications, always use a cutting lubricant or wax to reduce friction and carry heat away from the cutting edge.

Profile and Kerf: Choosing the Right Shape

Not all blades are shaped the same. The profile of the blade determines its intended use:

• Taper-Back Blades: These have a sloped nose, making them ideal for plunge cuts (starting a hole in the middle of a wall).
• Rectangular (Demo) Blades: These are wider and heavier, designed to resist the "wobble" and bending common in high-stress demolition.

Furthermore, consider the Kerf (Thickness). Thin Kerf blades (.035" thickness) are more flexible and cut faster because they remove less material. However, for extreme demolition, Heavy-Duty blades (.050" to .062" thickness) provide the rigidity needed to stay straight in deep cuts and resist snapping when the saw binds in structural lumber.

Types of Reciprocating Saw Blade: Specialized Applications and Materials

Consider Safety: The Importance of the Saw Shoe

The saw shoe (or foot) at the bottom of the blade is essential for controlling the tool. You should always hold the shoe firmly against the cutting surface.

This action counters the blade's tendency to push or pull during its reciprocal movement. By utilizing the shoe as a fulcrum, you minimize vibration, reduce the risk of kickback, and extend the life of the blade by preventing it from flexing excessively at the shank.