I use a micrometer the rotor should have minimum thickness stamped on the rotor is inches or millimeters
The thickness of brake rotors are measured with a tool called a caliper. The specifications for the particular car will show the minimum thickness that a rotor can still be used.
The rotor thickness for your 1997 Pontiac Bonneville is 0.75. When the rotor falls below this thickness a certified mechanic can no longer use the rotor.
Look up the vehicle on Autozone.com and then click on the specifications page. You will need a micrometer to measure the rotor.
2004 ford explorer minimum rotor thickness
Front Rotor Minimum Thickness after machining the rotor is .996
The brake rotor thickness for your 2003 Mitsubishi Eclipse, is 0.75. The rotor should not be used if the thickness is less than this.
The minimum thickness is cast into the rotor, either on the edge of the rotor or into the rotor hub.
The minimum front brake rotor thickness is three aids of an inch. When the rotor does not have the minimum thickness the auto mechanic replacing the brakes can not use the rotor.
The rear rotor thickness should be three quarters of an inch, when new. The rotor should not be reused when the thickness is less than one half inch.
The 2001 Pontiac Grand Am minimum brake rotor thickness is .075. The minimum brake rotor thickness is a standard minimum. Certified mechanics cannot use the brake rotor when the thickness drops below this level.
The minimum thickness should be cast somewhere on the rotor.