A hacksaw blade is a narrow, replaceable strip of toothed steel that mounts in a hacksaw frame to hand-cut metal, plastic, and other hard materials; blades come in various lengths, materials, and teeth-per-inch (TPI) ratings to match the task, and are tensioned in the frame so the teeth cut smoothly on the push stroke.
What is a hacksaw blade?
A hacksaw blade is a thin, toothed metal strip designed for hand cutting. It fits into a hacksaw frame, which stretches the blade under tension so it cuts accurately and resists bending. Most blades are designed to cut on the push stroke, with the teeth pointing away from the handle. They’re inexpensive, easy to swap, and tailored to different materials through tooth count (TPI), blade material, and tooth design.
Common DIY uses
Hacksaw blades are a go-to for cutting:
- Steel and stainless-steel bolts, screws, and threaded rod
- Metal pipe and conduit (EMT, copper, brass, aluminum)
- Thin steel bar, angle, and perforated strapping
- Plastic pipe (PVC, CPVC, ABS) and plastic trim
- Miscellaneous shop tasks: trimming nails, freeing stuck fasteners, and rough shaping metal parts
If you’re trimming closet rod, cutting bolts for a toilet flange, shortening a curtain rod, or resizing a length of copper pipe, the right hacksaw blade gets it done with hand power and a bit of patience.
Types and variations
Hacksaw blades vary by length, tooth count, material, and tooth pattern.
Length:
- 12-inch (300 mm): Most common for standard hacksaw frames.
- 10-inch (250 mm): Used in some adjustable frames.
- 6-inch (150 mm): Junior or mini hacksaw blades for tight spaces.
Teeth per inch (TPI): Tooth density affects cut speed and smoothness.
- 14–18 TPI: Coarser, faster cutting on thicker stock.
- 18–24 TPI: General metal cutting.
- 24–32 TPI: Very fine, for thin-wall tubing and sheet metal to prevent snagging.
Blade material:
- High-carbon steel: Budget-friendly, flexible, dulls faster on hard metals.
- High-speed steel (HSS): Harder teeth, stays sharp longer, more brittle.
- Bi-metal (HSS tooth edge bonded to spring steel back): Combines durability and flexibility; best all-round choice for DIY.
- Carbide grit or carbide-toothed: For very hard or abrasive materials (hardened steel, ceramics) where standard teeth won’t bite.
Tooth set and form:
- Wavy set: Slight alternating bend through groups of teeth; good for thin stock and tubing.
- Raker or alternate set: Common on general-purpose blades; balances speed and smoothness.
Kerf and thickness: Thicker blades track straighter and are less prone to twisting; thinner blades fit tighter cuts but can wander if pushed too hard.
How to choose the right blade
Match the blade to the material and thickness:
- Thick steel bar, large bolts, or solid sections (>1/8 in or 3 mm): 14–18 TPI, bi-metal or HSS.
- General steel pipe, conduit, aluminum extrusions (1/16–1/8 in or 1.5–3 mm wall): 18–24 TPI, bi-metal.
- Thin-wall tubing, sheet metal (<1/16 in or 1.5 mm): 24–32 TPI, wavy set to prevent tooth snag.
- Copper and brass: 18–24 TPI works well; light oil helps, especially on brass to reduce chatter.
- Stainless steel: 18–24 TPI bi-metal or HSS; use steady pressure and cutting fluid.
- Plastics (PVC, CPVC, ABS): 14–18 TPI to clear chips; use light pressure to avoid melting. A fine wood/plastic blade can also work.
- Hardened steel (tempered bolts, hardened pins): Consider a carbide grit blade or use a power tool designed for hardened materials.
Other selection tips:
- If the workpiece is thin, aim for at least 2–3 teeth in the cut at all times to avoid tooth catch. That usually means higher TPI.
- For general household tasks, a 24 TPI bi-metal blade is a good starter. Add 18 TPI and 32 TPI to cover thick and thin stock.
- Choose bi-metal if you want blades that resist snapping and last longer under tension.
How to use a hacksaw blade effectively
- Mark and start the cut:
- Measure and mark a clear line. Use a file or the blade’s corner to score a shallow groove to guide the first strokes.
- Secure the work:
- Clamp the part firmly in a vise or to a stable surface. Keep the cut close to the support to reduce vibration.
- Install and orient the blade:
- Teeth pointing forward (away from the handle) for cutting on the push stroke. Tension the blade firmly; it should make a clear “ping” when plucked.
- Use full, smooth strokes:
- Keep the saw level and use as much blade length as possible to distribute wear. Let the teeth do the work; use moderate pressure on the push and lighter pressure on the pull.
- Lubricate for metal:
- A drop of cutting oil reduces heat and extends blade life, especially on steel and stainless. Wax works well on aluminum to prevent clogging.
- Control heat and chips:
- If the cut gets hot, pause to clear chips. For plastics, use slower strokes to avoid melting and chattering.
- Finish cleanly:
- As you near the end, reduce pressure to avoid tearing or bending the last bit. Deburr edges with a file.
Pro tip: Many frames let you rotate the blade 90 degrees to saw flush to a surface or in tight quarters. Mini or junior hacksaw frames are handy in cramped spaces under sinks or inside cabinets.
Maintenance and storage
- Replace blades when they feel slow, require excess force, or have missing teeth.
- Keep blades dry and lightly oiled to prevent rust.
- Store spares in a sleeve or wrapped to protect the teeth.
- Don’t reuse a blade after it’s kinked or twisted; it will wander and is more likely to snap.
Common mistakes to avoid
- Wrong TPI: Too coarse on thin stock causes snagging; too fine on thick stock clogs and overheats.
- Low tension: A slack blade wanders and chews the kerf. Tighten until firm and musical when plucked.
- Excess pressure: Forcing the cut breaks teeth and twists the blade. Let the teeth bite at a steady rhythm.
- Short strokes: Using only the middle of the blade wears it out quickly. Use full strokes to spread the work.
- Poor support: Cutting an unsupported end leads to vibration and crooked cuts. Clamp close to the cut line.
- Backward blade: Teeth should face forward for push cutting unless a specific task calls for pull cutting.
Related terms
- Hacksaw frame
- Junior hacksaw / mini hacksaw
- Reciprocating saw metal-cutting blade
- Coping saw (for wood and plastics)
- Cutting fluid / thread-cutting oil
Practical examples
- Trimming toilet bolts: Fit a 24–32 TPI bi-metal blade, protect the porcelain with tape, and saw with light pressure near the nut for a clean finish.
- Shortening threaded rod for shelving: Use 18–24 TPI, double-nut the rod at the cut line to protect threads, saw, then back off the nut to clean the threads.
- Cutting copper pipe for a sink trap: Mark the length, clamp gently to avoid deforming the tube, use 24 TPI and light oil, then deburr inside and out for a leak-free joint.
- Freeing a rusted screw head: If slots are stripped, saw a deeper single slot across the head with a fine blade and use a flat screwdriver.
A small pack with 18, 24, and 32 TPI bi-metal hacksaw blades will handle most home projects and deliver smoother, safer cuts with less effort.