Short definition
A reciprocating saw is a power saw with a long replaceable blade that moves back and forth at high speed. It cuts copper, galvanized, cast iron, ABS, PVC, wood-with-nails, drywall, and lath-and-plaster. “Sawzall” (the Milwaukee brand) is genericized. It is the in-wall and demo workhorse of plumbing.
What it is
Stroke length runs 1 inch (compact) to 1 1/4 inch (standard). Strokes per minute go up to about 3,000 with variable trigger control. Blades are graded by teeth-per-inch and material:
- 6 TPI bi-metal — wood with nails
- 10 to 14 TPI bi-metal — copper, galvanized
- 18 to 24 TPI — steel, cast iron
- Carbide grit — cast iron, terra cotta
Bi-metal blades are the all-around plumbing default. Carbide for cast iron specifically.
Why it matters to a homeowner
A recip saw earns its place in any repipe, repair, or demo job. Cutting an old galvanized supply line out of a wall, removing a section of cast iron stack for a no-hub repair, sawing through a stuck garbage disposal mounting ring — all faster with a recip than with a hacksaw, and faster than calling a plumber.
The non-negotiable warning: don’t plunge a recip blind. “Sawzall through a live wire” is a trade in-joke because it happens often. Confirm what’s behind the drywall before plunging — water, gas, or electrical lines run in places drawings don’t always show.
Common variants and not the same as
- Reciprocating saw vs. jigsaw. Jigsaw is for finer, controlled curves on flat material. Recip is for demo, blind cuts, and heavy material.
- Reciprocating saw vs. hacksaw. Recip is faster but less controlled. Hacksaw for surgical work near other plumbing or wiring.
- Reciprocating saw vs. angle grinder. Grinder cuts harder material faster but throws sparks and dust. Recip is safer indoors.
Common failure modes
- Bound kerf. Cut pipe drops onto the blade and pinches it. Snaps the blade. Cut slowly.
- Cut through a hidden line. Verify routing before plunging.
- Hot blade. Burns on contact after extended cutting. Wait or swap.
- One-handed for hours. Hand-arm vibration. Use the two-handed grip when possible.