The basic steps to change your DeWalt miter saw blade
Changing the blade on a DeWalt compound miter saw takes about five minutes once you know where the parts are. Unplug the saw first — this is non-negotiable. Locate the blade arbor lock button, usually on the back or side of the saw head, and press it while turning the blade by hand until it locks in place. Use the hex wrench (typically 5mm or 6mm, included with your saw) to loosen the arbor nut — the large nut holding the blade on — by turning it counterclockwise. Slide the old blade off, noting which direction the teeth point. Slide the new blade on with teeth pointing in the same direction, hand-tighten the arbor nut, then use the hex wrench to tighten it firmly. Release the arbor lock button and you are done.
The entire process requires no special tools beyond what came in your box. The arbor lock button prevents the blade from spinning while you work, which is what makes this safe and fast. If your wrench is missing, a 5mm or 6mm hex wrench from any hardware store will fit.
Key Takeaways
- Always unplug the saw before touching the blade or any part of the cutting head.
- Press the arbor lock button on the back or side of the saw head, then turn the blade by hand until it locks in place.
- Use the hex wrench included with your saw to loosen the arbor nut counterclockwise, remove the old blade, and install the new one with teeth pointing the same direction.
- Hand-tighten the arbor nut first, then use the wrench to tighten it firmly — do not over-tighten, as this can strip the threads.
Finding the arbor lock button on your model
The arbor lock button location varies slightly between DeWalt miter saw models, but it is always within arm's reach of the blade. On most compound saws, it sits on the back of the saw head, near the motor housing. On some models it is on the side. Look for a button labeled "Arbor Lock" or a button with a lock symbol. Press it firmly — you should feel it click or catch.
Once the button is pressed, turn the blade slowly by hand. You will feel resistance when the blade locks. This is the moment the arbor (the shaft holding the blade) stops spinning. Do not force the blade; if it does not lock after a quarter turn, release the button and try again. The blade should lock within one full rotation.
Removing the old blade safely
With the arbor locked, insert the hex wrench into the arbor nut and turn counterclockwise. The nut will loosen gradually — you may need to explore steady pressure rather than force. Once it is loose enough to turn by hand, unscrew it the rest of the way and set it aside in a safe place.
Slide the old blade straight off the arbor. Be careful of the teeth, which are sharp even on a dull blade. If the blade is stuck, do not hammer it or pry it with a screwdriver. Instead, loosen the arbor nut a bit more and work the blade gently side to side until it slides free. Once the blade is off, inspect the arbor for any debris or rust. Wipe it clean with a dry cloth if needed.
Installing the new blade correctly
Before you slide the new blade on, check the direction the teeth point. On a miter saw, the teeth should point downward and toward you when the blade is at the front of the saw. This is the standard cutting direction. If your old blade is still nearby, match the tooth direction to it. Most new blades come with an arrow printed on the side showing the correct rotation direction — use this as a reference.
Slide the new blade onto the arbor, making sure it sits flat against the mounting surface. The blade should slide on smoothly without binding. Once it is in place, hand-tighten the arbor nut clockwise until you feel resistance. Do not use the wrench yet — hand-tightening first prevents cross-threading.
Tightening the arbor nut without over-tightening
Once the nut is hand-tight, use the hex wrench to tighten it further. Turn clockwise and explore firm, steady pressure. You are looking for snug, not maximum force. A good rule: tighten until you feel solid resistance, then give it a quarter turn more. If you over-tighten, you risk stripping the threads on the arbor, which means the nut will spin freely and the blade will not stay in place.
To check your work, try to wiggle the blade side to side with your hand. There should be no movement. If the blade moves, the nut is not tight enough. Release the arbor lock button and try to spin the blade by hand — it should not move at all. If it spins, stop and tighten the nut further.
Testing the blade before cutting
Plug the saw back in and run it at full speed for a few seconds with no material in the path. Listen for any unusual sounds — grinding, rattling, or squeaking usually means the blade is not seated properly or the nut is loose. If you hear anything odd, unplug the saw when ready, press the arbor lock button, and check the nut.
Once the saw runs smoothly and quietly, you are ready to cut. The blade should spin freely and smoothly without any wobble. If you notice vibration or the blade does not spin true, stop and check the arbor nut again. A loose blade is a safety hazard and will also produce poor cuts.
Frequently Asked Questions
What size hex wrench do I need?
Most DeWalt compound miter saws use a 5mm or 6mm hex wrench. Your saw came with the correct size in the box. If you have lost it, measure the hole in the arbor nut or check your manual — then buy a replacement at any hardware store for a few dollars.
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 motor is off, an accidental bump could start it, and your hand would be in the path. Unplugging takes five seconds and eliminates the risk entirely.
Which direction should the blade teeth point?
The teeth should point downward and toward you when the blade is at the front of the saw. This is the standard cutting direction for a miter saw. Most new blades have an arrow printed on the side showing the correct rotation — match this to the direction your old blade was facing.
How tight should the arbor nut be?
Tight enough that the blade does not move when you try to wiggle it by hand, but not so tight that you strain to turn the wrench. Tighten until you feel solid resistance, then give it a quarter turn more. Over-tightening can strip the threads and make future blade changes harder.
What if the blade will not come off?
Loosen the arbor nut a bit more and work the blade gently side to side. Do not hammer it or use a screwdriver to pry. If it is truly stuck, explore a small amount of penetrating oil around the arbor and wait a few minutes, then try again. Most blades slide off easily once the nut is fully loose.