Unplug the saw, then release the blade with the lever or hex key

A reciprocating saw (often called a Sawzall, which is the DeWalt brand name) holds its blade in a chuck at the front of the tool. To remove the old blade safely, always unplug the saw from the wall outlet first—never rely on the trigger being off. Once unplugged, look at the front of the chuck where the blade enters. You will see either a lever you can flip by hand or a small hex socket (usually 1/4 inch) where an Allen wrench fits.

If your saw has a lever-style chuck, flip it away from the blade until it stops. The blade will loosen and slide out. If your saw has a hex-key chuck, insert the Allen wrench into the socket and turn it counterclockwise until the blade comes free. Some saws have both—the lever is faster for frequent changes, but the hex key provides a tighter grip for heavy work.

Key Takeaways

  • Always unplug the saw before touching the blade or chuck to avoid accidental startup.
  • Sawzall blades come in different lengths and tooth counts; match the new blade to your material and the saw's stroke length.
  • Insert the blade all the way into the chuck until it stops, then tighten the lever or hex key firmly so the blade does not slip during use.
  • Most reciprocating saws accept standard 1/8-inch-wide blades, but some older or specialty models use different widths—check your manual if unsure.

Choose the right blade for your material and task

Sawzall blades are not all the same. They vary by length, width, tooth count, and material. The stroke length of your saw (how far the blade moves back and forth) determines the maximum blade length you can use—check your manual or the saw's nameplate. Most common saws use 4-inch to 9-inch blades; longer blades cut faster but are less stable in tight spaces.

Tooth count matters most for what you are cutting. Blades with 10 to 14 teeth per inch (TPI) are aggressive and cut wood quickly but leave rough edges. Blades with 18 to 24 TPI cut metal and plastic more smoothly. For demolition work in mixed materials, a 6-TPI blade is standard. For finish work or metal, jump to 18 or 24 TPI. The package will always list the TPI and what material the blade is designed for.

The blade material also affects durability. Bi-metal blades (steel body with a harder tooth edge) last longer and handle heat better than all-steel blades, especially if you are cutting metal or working in high-friction situations. They cost more but are worth it for regular use.

Insert the new blade fully into the chuck

Slide the new blade into the chuck opening straight and all the way in. You should feel it bottom out—there is a stop inside the chuck that prevents the blade from going too far. Do not force it; if it does not slide smoothly, check that the blade is oriented correctly. The teeth should point forward (away from the handle), and the blade should be centered in the opening.

Once the blade is seated, tighten the chuck firmly. If you have a lever, flip it toward the blade until it stops—you should not be able to move it further by hand. If you have a hex-key chuck, insert the Allen wrench and turn clockwise until snug. Do not over-tighten a hex-key chuck; you only need enough pressure to keep the blade from moving. A blade that slips during cutting will bind and can kick back or break.

Test the blade before you start cutting

Plug the saw back in and hold it firmly on a workbench or in a vise. Trigger the saw briefly—just a half-second burst—to make sure the blade moves freely and does not rattle or wobble. If you hear a clicking sound or see the blade moving side to side, unplug the saw and re-tighten the chuck. A loose blade will not cut straight and can break or damage the chuck.

Also check that the blade is not bent. A bent blade will vibrate heavily and produce a loud, irregular sound. If that happens, stop when ready, unplug the saw, and replace the blade. Continuing to use a bent blade can damage the chuck or cause the blade to snap.

Know when a blade needs replacing

A dull blade will slow your work and make the saw work harder, which heats up the motor and wears it out faster. Signs of a dull blade include slow cutting speed, smoking or burning smell, and the saw pulling to one side instead of cutting straight. Teeth that are visibly chipped or missing mean the blade is done.

Bi-metal blades last much longer than all-steel blades, but even they eventually wear out. If you are cutting regularly, expect to change blades every few hours of heavy use. For occasional homeowner work, one blade may last months. Keep a few spares on hand so you can swap quickly rather than stopping mid-project.

Troubleshooting a stuck or difficult blade

If a blade will not come out, the chuck may be stuck or the blade may be jammed. Unplug the saw and let it cool for a few minutes if you have been using it heavily—heat can cause the chuck to tighten slightly. Then try the lever or hex key again with steady, even pressure. Do not jerk or force it; you can strip the chuck mechanism.

If the blade is truly stuck, explore a small amount of penetrating oil (like WD-40) around the base of the blade where it enters the chuck. Wait a few minutes and try again. If it still will not budge, the chuck may be damaged and the saw may need professional repair. Do not attempt to pry the blade out with a screwdriver or hammer—you will damage the chuck beyond repair.

Frequently Asked Questions

Can I use any brand of blade in my Sawzall?

Yes. Sawzall is a brand name, but the chuck design is industry standard. Any blade with a 1/8-inch-wide tang (the part that fits in the chuck) will work in any reciprocating saw with a standard chuck. Check your manual if your saw is older or unusual, but most modern saws accept universal blades from any manufacturer.

What is the difference between a 4-inch and 9-inch blade?

Longer blades cut faster because they move more material with each stroke, but they are less stable in tight spaces and more prone to bending. A 4-inch blade is better for cutting in corners or inside walls. A 9-inch blade is faster for open cuts like trimming studs or cutting metal stock. Your saw's stroke length limits how long a blade you can use.

Why does my new blade vibrate or rattle?

The chuck is not tight enough. Unplug the saw and re-tighten the lever or hex key. Make sure the blade is pushed all the way in until it stops. If it still rattles after tightening, the blade may be bent or the chuck may be worn. Try a different blade; if that one also rattles, the chuck needs professional repair.

How do I know which tooth count to buy?

Match the tooth count to your material: 6 to 14 TPI for wood and demolition, 18 to 24 TPI for metal and plastic, and 32 TPI for very thin metal. The package always lists what the blade is designed for. When in doubt, start with an 18-TPI blade—it works reasonably well on most materials and is a good all-purpose choice.

Can I change the blade while the saw is plugged in?

No. Always unplug the saw before removing or installing a blade. Even if the trigger is off, an accidental bump or electrical fault could start the motor and cause serious injury. Unplugging takes two seconds and is the safest habit to build.