Symptoms
- Cuts don't sit flush when joined at a corner
- 0-degree cuts aren't actually square
- Angle scale doesn't match the actual cut angle
- Miter joints leave visible gaps
Likely causes
- CommonMiter saw fence not square to the bladeA fence that's off by even a degree throws off every angled cut.
- CommonBevel angle not calibrated to true 0 or 90 degreesFactory stops can drift from vibration and repeated use.
- PossibleBlade not perpendicular to the tableA tilted blade cuts an angle even when the saw reads square.
- PossibleMaterial shifting during the cutUnclamped stock can move slightly and skew the angle.
- PossibleDull or bent bladeA damaged blade can wander off the intended line.
What to do
- Use a reliable square to check that the fence is exactly 90 degrees to the blade at the 0-degree stop.
- Check the bevel angle against the table with the square as well, since both need to be accurate.
- Loosen the fence mounting bolts and adjust as needed if it's off, then retighten firmly.
- Recalibrate the miter and bevel stops per the saw's manual if adjustment screws are provided.
- Clamp the workpiece firmly instead of holding it by hand to prevent shifting during the cut.
- Make a test cut on scrap and check it against the square before cutting your actual project pieces.
Tools and parts
- Miter saw
- Engineer's or speed square
- Screwdriver
- Clamps
When to call a pro
If recalibration doesn't bring the saw back to square, a tool repair shop can check for a bent table, arm, or fence.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.