Reading the Brake Drum Micrometer
To properly use the brake drum micrometer you must be able to convert fractions into decimal form.
Example: 9 1/2 inches = 9 + (1÷ 2) = 9.5
1) 8 1/4 inches = ___________
2) 10 3/4 inches = __________
3) 10 7/8 inches = ___________
4) 11 1/8 inches = __________
Part of the drum brake micrometer is laid out like a ruler. Below is a view of the ruler part.
You can see that the Left frame is ready to measure either a 10 or 11 inch drum.
The right frame is set to measure either a 9 or 10 inch drum.
5) What is this drum micrometer, shown above, set to measure? _______________________
6) What is this drum micrometer, shown above, set to measure? _______________________
7) What is this drum micrometer, shown above, set to measure? _______________________
8) What is this drum micrometer, shown above, set to measure? _______________________
9) What is this drum micrometer, shown above, set to measure? _______________________
10) What is this drum micrometer, shown above, set to measure? _______________________
11) What is this drum micrometer, shown above, set to measure? _______________________
12) What is this drum micrometer, shown above, set to measure? _______________________
The final step in reading the drum micrometer is to read the dial that is calibrated to .001”
This dial reads .045”
14) ________
16) The drum micrometer shown above reads ______________________
13) __________
15) ____________
17) The drum micrometer shown above reads ______________________
18) The drum micrometer shown above reads ______________________
19) The drum micrometer shown above reads ______________________