Find the first part that moves. An off-center lump, a rocking bat, a shifting table and an abnormal wheelhead are different faults to investigate. Adjusting the machine before making that distinction can hide the original problem.
Begin below the wheel
With the machine stopped, inspect its support and ordinary leg fittings as the manual permits. A table that shifts as you take your working position makes later observations unreliable. Resolve that movement before operating the wheel.
Use the approved installation or leveling method. A loose stack of scraps under one side may appear level at rest and still move under pressure. Check the complete support rather than watching only the rotating surface.
Then separate the bat from the clay
Disconnect power, remove the work and inspect the bat fitting. Trapped clay, the wrong hole pair or damaged attachment parts can prevent proper seating. Clean these surfaces before deciding that the bat or head is defective.
Set the clean bat on a known flat surface and see whether it rocks there. If it does, take it out of use until its condition is resolved. If it sits flat elsewhere but not on the wheel, investigate the fitting instead of buying a replacement at random.
Observe without adding a measuring hazard
If there are no warning symptoms and the setup passes those checks, observe ordinary operation as the manual allows. Keep fingers, rulers and improvised pointers away from the rotating edge. A video from a safe distance can show support the movement without pretending to measure mechanical runout.
Record whether the movement appears in the pot, the bat or the bare head. Lighting and camera angle can mislead, so describe what you saw rather than concluding that a shaft is bent.
Use the observation to choose the next route
If only the clay is uneven and the equipment operates normally, ask an instructor to watch centering and hand release. Do not change wheel hardware to correct a shape disturbed during throwing.
If the bare head appears to move abnormally, stop and contact the manufacturer. Do not loosen bearings, strike the head or follow a generic shaft-adjustment suggestion. For a new wheel, document the symptom and any shipping damage before making modifications that could complicate a return.
Questions about this topic
Does wobble always mean a bent wheelhead?
No. The support, bat attachment and clay can each create visible movement. Separate them before requesting a diagnosis.
Should I add a cloth under a rocking bat?
Not before identifying the cause. Use a support accessory only as part of a compatible, instructed bat arrangement.