AFS Foundry Sand Testing Equipment Operating Instructions Manual

RIDSDALE-DIETERTGREEN HARDNESS TESTER ‘C’ SCALE (cont’d)IIITEST PROCEDURE (cont’d)(c)(d)(e)When testing in places where the dial cannot be seen easily, hold the pointer in thetest position by pressing the locking button on the front of the tester. Remove theinstrument from the mould and take the reading.The pointer is released ready for the next test by pressing the button on the back ofthe tester while holding the thumb on the probe to prevent the sudden return of thepointer to zero and hence possible damage.Readings are empirical and bear no direct relationship to any definite pressure perunit area. They are, however, valuable for comparative purposes.124