Dial Caliper Introduction
A Six-Inch Dial Caliper is a precision-measuring tool that measures
accurately to within .001 of an inch. Although it is not as accurate as a
Vernier Scale Micrometer (which can read to within .0001 of an inch), the
Six-Inch Dial Caliper is more versatile.
You can use the Six-Inch Dial Caliper to measure distance from 0 to 6
inches for inside, outside, and depth measurements. Because of its
versatility, you will use this tool frequently.
A Dial Caliper has jaws that contact inside and outside surfaces during
measurements, and a rod connected to a slide for obtaining depth
dimensions. The end of the rod is notched to provide a nib for measuring
small grooves and recesses.
All readings are taken directly from the bar and dial-indicator. Knurled
thumbscrews lock the movable jaw and adjustable indicator dial.
With the addition of a depth attachment, the Dial Caliper becomes as
convenient and easy to use as a depth gauge.
Parts of the Dial Caliper
The major parts of the Dial Caliper are labeled on the diagram and described
A. Bar: A scale with graduations in inches and tenths of an inch.
B. Fixed Jaws: Located at the zero end of the scale on the bar, the
fixed jaws function as the starting points for inside and outside
C. Moveable Jaws: Can be slid along the bar in order to take inside
and outside readings.
D. Dial: The dial hand makes one complete revolution for each .10
inch of movement. The face is divided into increments of .001.
E. Moveable Jaw Clamp Screw: This locks the movable jaws into
F. Adjusting Nut: This is used to adjust to the dial so that it registers
zero when the caliper jaws are closed.
G. Depth Bar: Used to take depth measurements of holes, steps, and
Reading the Dial and Bar
Once you have placed the jaws in the space or around the part that you want
to measure, you need to read both the bar and the dial to get a reading.
The bar is in increments of inches and tenths. As you slide the bar to the
right, new increments appear from under the dial. In Figure 4- 2, the reading
is something over .700”.
One full rotation of the dial (zero to zero) represents a movement of .100
inch. The dial reads in thousandths and ten thousandths.
In the above picture, the last line visible on the bar is .700 and the dial reads
.050, so the reading on this measurement is .750.
In this example, the bar reads 3 tenths and the dial reads 12 thousandths, so
the reading is:
.300 + .012 = .312”
Skill Check 1 - Dial Caliper
Read the bar and dial in each photo below, then record your reading in the
space provided. When you are done, check your answers with the answer
key following this Skill Check.
1. This reading is :_________________ inches.
2. This reading is :_________________ inches.
1. 3. 3. This reading is :________ inches.
2. 3. 4. This reading is :________ inches.
3. 3. 5. This reading is :________ inches.
4. 3. 6. This reading is :________ inches.
5. 3. 7. This reading is :________ inches.
6. 3. 8. This reading is :________ inches.
7. 3. 9. This reading is :________ inches.
8. 3. 10. This reading is :________ inches.
Skill Check 1 Answers
Below are the answers to the previous exercise. How did you do? If you
missed more than 3 you may want to do a little more practice reading the
dial. If you got them all right, congratulations!