A dial caliper is a precision measuring device that is normally used for measuring the thickness of materials and small amounts of movement. In the automotive industry, there are a number of different uses for a dial caliper, also known as a dial indicator. There are also other industries where a dial caliper can be very useful. Some of the various uses are listed below.
1. Measuring Thickness
A mechanic will use a dial caliper to measure the thickness of brake rotors. This is important because if a brake rotor becomes too thin, it can shatter, causing loss of brakes. Another reason a mechanic will use a dial caliper to measure the thickness of a brake rotor is to determine what is known as run-out, a condition where the thickness of the brake rotor changes across its surface. A dial caliper will be used anywhere that the thickness of a given piece of material needs to be known. This type of calipers is called an outside thickness caliper. Some of these places are listed below.
- Auto repair facilities
- Machine shops
- Fabrication plants
2. Measuring Deflection
Deflection is the movement off of a center line that a given part is able to move. In the automotive repair industry, a mechanic will use a dial caliper with different types of clamps to measure the wear of certain suspension-related parts by measuring the deflection or movement of these parts when a load or strain is placed upon them. Some of the parts that a mechanic may use a dial caliper to measure the deflection and wear of are listed below.
- Ball joints-On some cars, ball joint deflection measurement determines whether replacement is required. This is done by lifting the vehicle’s front end a few inches off the ground and prying upward on the tire and measuring the amount of deflection, or motion up and down that the ball joint allows. Excessive deflection means the ball joint is worn and requires replacement.
- Steering gear box Pitman arms-The steering gear box and Pitman arm translate driver steering wheel input into sideways motion of the tires for steering. Excessive Pitman arm wear can cause steering problems, as well as alignment issues.
- Steering gear box wear-A dial caliper properly mounted measure how much movement of the steering wheel is required to cause movement of the wheels.
- Steering rack wear-Measuring steering rack and pinion wear can help determine if the rack is close to failure. Measuring both up and down deflection of the rack will tell you if the bushings are excessively worn and measuring how much steering input is required to move the wheels will help you adjust a steering rack.
3. Measuring Width
Another measurement that a dial caliper is able to make is width. The main part that a mechanic will need to measure the width of is a brake drum. If a brake drum becomes too wide, it too can shatter and cause complete loss of brakes. This type of caliper is known as an inside diameter caliper.