my makita saw blade is wobbling and the cut is all over the place. did i install it wrong?

Diagnosis

A wobbling blade on the Makita XSH03Z is almost always caused by a failure in the "sandwich" of components between the arbor nut and the blade body. The most common culprit is the missing or misplaced outer flange (the washer that sits on top of the blade). If the blade is not perfectly centered and clamped flush against the inner flange, it will create an eccentric rotation. This causes the blade to "walk" or oscillate, leading to wavy cuts and dangerous vibration that can strip the motor bearings over time. Another frequent cause is the use of a blade with an incorrect arbor hole diameter. The XSH03Z requires a precise fit; if you are using a blade with a slightly oversized center hole without the proper reducer ring, the blade will not sit concentric to the spindle. You can confirm this by spinning the blade slowly by hand (with the battery removed) and watching the gap between the blade edge and the base plate; if the gap widens and narrows during a rotation, the blade is out of alignment.

How to Fix It

Follow these exact steps to ensure a true, concentric mount:

1. Remove the 18V LXT battery immediately to prevent accidental startup.
2. Using the provided wrench, unscrew the arbor bolt. Remove the outer flange (the washer) and the blade.
3. Clean the spindle and both flanges with a rag to remove sawdust or metal shavings. Even a tiny grain of debris can throw off the center of the blade.
4. Verify your blade size. Ensure you are using a 165mm (6-1/2") blade. Check the arbor hole diameter; it must match the XSH03Z spindle exactly.
5. Place the inner flange onto the spindle. Slide the blade onto the spindle, ensuring the teeth are pointing downward toward the front of the saw.
6. Place the outer flange on top of the blade. This is the critical step: the flange must sit completely flat against the blade. If it is tilted, the blade will wobble.
7. Hand-tighten the arbor bolt to ensure it is not cross-threaded, then use the wrench to tighten it firmly. Do not over-torque to the point of bending the bolt, but ensure it is snug enough to prevent the blade from slipping during a heavy rip cut.
8. Perform a "dry spin" by rotating the blade by hand to verify there is zero lateral movement.

If That Didn't Work

• Inspect the Spindle for Bending: If the blade still wobbles after a correct reinstall, the arbor spindle itself may be bent. This usually happens if the saw was dropped on its side while the blade was attached. Check this by spinning the spindle without the blade; if the shaft itself is oscillating, the tool requires a professional gear-case replacement.
• Check for Flange Warping: Inspect the inner and outer flanges for any signs of bowing or deformation. If a flange is warped by even a fraction of a millimeter, it will push the blade off-center. Replace warped flanges with genuine Makita replacement parts.
• Verify Blade Quality: Cheap, off-brand blades often have inconsistent centering (runout). Swap the current blade for a high-quality Makita Pro Grade or Diablo blade to see if the wobble disappears. If a premium blade runs true, the previous blade was defective.
• Examine the Base Plate: Ensure the base plate is not bent or warped. If the shoe is not sitting flat on your workpiece, the saw will tilt, making the cut look "all over the place" even if the blade is spinning perfectly true.

Heads Up

• Never Mix Hardware: Only use the bolt and flanges that came with the XSH03Z. Using bolts from a different brand or model may result in a different thread pitch or flange depth, leading to catastrophic blade failure.
• Check Tightness Regularly: Vibration from cutting hardwoods can loosen the arbor bolt. Check the tightness of your blade every 20-30 minutes of active use.
• Battery Safety: Always remove the battery before changing blades. The XSH03Z is a high-torque tool, and an accidental trigger pull during a blade change can cause severe injury.
• Avoid Over-tightening: While the bolt must be secure, using an impact driver to tighten the arbor bolt can strip the threads on the spindle, rendering the saw useless. Always use the manual wrench.