How to Use a Hacksaw

Woman using a hacksaw

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The traditional hand-operated hacksaw is no longer familiar to everyone, since corded and battery-powered jigsaws have emerged as workhorse tools for most DIYers. And it's true that a power jigsaw or reciprocating saw mounted with the right kind of blade can serve most of the functions performed by a hacksaw. But, as every professional plumber knows, the hacksaw still has its place, and if you don't own one, you owe it to yourself to add it to your tool collection if you do frequent plumbing projects.

In addition to being an inexpensive tool, a hacksaw has a very long cutting surface that is ideal when you are cutting large pipes and has fine teeth that are great for cutting metals smoothly. As a classic plumber's tool, a hacksaw is primarily a tool for cutting metals, such as steel pipes or sheet metal, but it can also be very useful for cutting plastic pipes when you don't have a specialty tool designed for that purpose.

The key to using hacksaw effectively is to understand the various blades available for the tool, and choosing the right one for the job.

Parts of a Hacksaw

The hacksaw is a very simple tool, consisting of an elongated C-shaped frame with a handle at one end, and a narrow, flexible blade that mounts on pegs and is stretched taut across the open side of the frame by means of a tightening knob or wingnut on the handle side of the frame. The blades can be discarded and replaced whenever they become dull.

Standard hacksaw
Hacksaws are useful for cutting many kinds of metal. This hacksaw frame is adjustable and can therefore accept blades of several different lengths. Source: Kris Jensen-Van Heste

There are also mini-hacksaw frames that allow one end of the blade to extend past the handle. These are well-suited for use in confined spaces, where a full-sized saw frame won't fit.

Mini hacksaw
Mini hacksaw

Amazon.com

Hacksaw vs. Reciprocating Saw

If you own a reciprocating saw, there are blades available that will let you do most of the same jobs as a traditional manual hacksaw. For example, a reciprocating saw fitted with a 12-inch metal-cutting blade can cut large cast-iron pipes quicker than a hacksaw. But the speed of the blade is also the disadvantage of a reciprocating saw, as the tool's blade can be hard to control and keep straight while you are cutting. A manual hacksaw, on the other hand, will cut at the speed you choose, making it possible to be much more precise.

Professional plumbers will use a reciprocating saw when speed is essential and when rough cutting is not a drawback. But for precision work, most plumbers still keep a manual hacksaw in the toolbox.

Hacksaw
  • Cuts slowly

  • Cuts precisely

  • Inexpensive

Reciprocating Saw
  • Cuts quickly

  • Can be hard to control

  • Expensive but versatile

Parts of a Hacksaw

A hacksaw is among the simplest of cutting tools. An elongated C-shaped metal frame has one end fitted with a handle. Hacksaw frames can be either fixed or adjustable. A fixed frame accepts one blade length. An adjustable frame typically handles 10- and 12-inch blades; some can accept blades ranging from 8 to 16 inches. There’s a slight price difference, but the versatility of an adjustable frame is well worth the additional cost.

A hacksaw blade has a hole at each end that fits onto pegs on the frame, and these pegs usually can be set in four positions: up, down, left, and right. Also, the blade can be mounted on the posts with the teeth pointing either direction, giving you a total of eight blade positions to choose from.

What Blade to Use

Hacksaw blades are available in several lengths to fit different handle sizes, and with tooth counts ranging from 14 to 32 teeth per inch (TPI). Thin stock calls for finer teeth; thicker metal requires fewer teeth per inch. The way teeth are positioned on a blade is called “set.” There are three typical tooth sets:

  • Regular: These work well on softer metals that don’t contain iron. The teeth are lined up touching each other and alternating to the left and right.
  • Raker: Perfect for cutting into thick metals. The teeth are placed in sets of three.
  • Wavy: The right choice for hard, thin metals. The teeth are set in a wave pattern from left to right for a smooth, fine cut.

Many blades now use bi-metal construction, using both high-carbon steel and traditional high-speed steel (HSS) to create blades with improved flexibility.

Safety Considerations

For best results when using a hacksaw, follow these practices:

  • Choose the correct blade for the material being cut.
  • Secure the blade with the teeth pointing forward if you want to cut on the push stroke; backward if you want to cut on the pull stroke.
  • Keep the blade rigid and the frame properly aligned. The blade should be very taut in the frame for efficient cutting.
  • Cut using strong, slow, steady strokes.
  • Use the entire length of the blade in each cutting stroke.
  • Keep saw blades clean, and use light machine oil on the blade to keep it from overheating and breaking.
  • Cut harder materials more slowly than soft materials.
  • Clamp thin, flat pieces that require edge cutting.
  • If you’re cutting pipe, always secure it in a vise before cutting.

How to Use a Hacksaw

  1. Mount the Blade

    Slide the mounting holes in the ends of the blade over the mounting pegs on the saw frame. You can mount the blade in either direction so that it will cut on the pull stroke or the push stroke. Americans are accustomed to saws that cut on the push stroke, and this is the normal way to use a hacksaw. But reversing the blade to cut on the pull stroke—as is the case with fine Japanese woodworking saws—sometimes gives you a better result when using a hacksaw.

    Tighten the mounting knob or wing nut to stretch the blade taut. Be careful not to overtighten the blade, as it is possible to break it. The blade should be fairly rigid when you press on it, but you should still feel a tiny amount of "give" if you twist the blade hard with your fingers.

  2. Draw a Cutting Line

    For precise cuts, draw a line on the pipe or other workpiece to provide a reference when cutting. This may not be necessary for rough cutting where precision is not important.

  3. Cut the Material

    Position the blade on the cutting line, then begin to cut using slow, steady strokes. It’s essential that you cut slowly, no more than one stroke per second; metal-on-metal produces tremendous heat and can quickly ruin a blade. A drop of oil on the blade helps reduce friction and keeps the temperature down. Overheated blades can quickly become dull.

    Tip

    During a long cutting session, it's not uncommon to need to retighten the blade if it warms up and stretches while you are cutting.

  4. Loosen the Blade Tension

    When you are finished cutting, loosen the knob or wing nut on the saw to loosen the tension on the blade. This will reduce stress on the frame and may prolong the life of the blades.

Buying vs. Renting

Though it's possible to rent one at a home improvement store or tool rental outlet, hacksaws are so affordable that most DIYers will want to own one, especially if you do occasional plumbing work. Hacksaws have lots of purposes, and sooner or later you will find uses for it.

Keeping a Hacksaw in Good Condition

Loosen the blade on your hacksaw (or remove it) after every use to reduce stress on the frame and blade. Always cut with a sharp blade, and wipe the tool dry if it gets wet during use. Cleaning it occasionally with a rag moistened with light machine oil will prevent rust from forming.

When to Replace Your Hacksaw

A good hacksaw will last for decades if you clean it regularly and keep it lightly oiled to prevent rust. But when the tightening knob or wing nut becomes corroded or hard to turn, it's time to replace the hacksaw. And if any parts break, this inexpensive tool should be replaced.