To ensure that your headjoint is correctly positioned, carefully insert the ringed end of the wooden cleaning rod in to the headjoint. if the cork is in the correct position.

The ring should be visable at at the centre of the embouchure hole. If the headjoint mark is to the right of centre, gently tighten the crown until the mark becomes centered. If it is to the left of centre, unwind the crown a small amount and gently push it in.

Check that the ring mark on the wooden cleaning rod is again visible in the centre of the embochure hole. Under no circumstances should any force be exerted during any of these processes.

If you are in any doubt contact your teacher or repair man.