Miter saw not cutting square: find the axis that moved
A cut can be out of square across the board face, through its thickness, or along a sliding path. Identify that axis before touching an adjustment screw.
Inspect the cut in three dimensions.
Mark the board face, edge, and reference end before a test cut. Place the cut face against a reliable square and note whether the gap appears across the width, through the thickness, or changes from front to back on a sliding cut. Each pattern points to a different axis.
Repeat with straight, stable scrap supported level with the table. One bowed board or a piece that rocks against the fence can imitate a calibration problem, so confirm the symptom on more than one prepared sample.
Inspect mounting, cleanliness, damage, and deflection first.
With power disconnected, remove and inspect the blade by the manual procedure. Clean flange faces, confirm diameter, arbor, RPM, kerf, rotation, and clamping hardware, and remove any cracked, warped, or chipped blade from service.
A thin, dull, resin-loaded, or unsuitable blade can deflect under side pressure. Make a controlled test with no twisting of the head. If the cut begins square and curves, investigate feed, blade stiffness, stock stress, and slide play rather than moving the fence immediately.
Square table, fence, bevel stops, and pointers by the manual.
Follow the manufacturer’s sequence because one reference often depends on another. Common procedures compare the blade body—not carbide teeth—with a square while power is disconnected, then adjust a fence, bevel stop, or pointer only at specified fasteners.
A pointer changes what the scale reports; a stop changes the physical position. Do not use a pointer correction to hide a mechanical error. Tighten fasteners evenly and recheck after locking the controls.
Prove the fix with paired and repeated cuts.
Make several square cuts from the same reference face, then flip or pair pieces to magnify error. Test a wide sliding cut separately from a narrow chop because rail or glide behavior may appear only over travel.
If results vary rather than repeating, check stock movement, clamp pressure, fence debris, support height, lock tension, and operator side load. Persistent or changing error after permitted calibration belongs with authorized service.
Questions readers ask before they start
Why is my miter saw square at the back but not the front?
Possible causes include slide-path misalignment, blade deflection, stock movement, a bent fence, or debris at the reference. Test the axes separately.
Should I square to the blade teeth?
Usually the manual specifies the blade body between carbide teeth, because teeth project alternately. Follow the exact procedure.
Can a new blade cause out-of-square cuts?
Yes if it is damaged, incorrectly mounted, unsuitable, deflecting, or exposes an existing alignment error more clearly.
Check the exact saw manual before changing or adjusting anything.
This page is grounded in OSHA machine-guarding and power-tool guidance plus current manufacturer manuals. The instructions for your exact model control every procedure.