1. Select gauge blocks from an 83 piece set to build up a dimension of 3.2265”
2. Use the Unilateral System for a GO/NO-GO gauge design if the calibrated temperature is 72°F and the actual room temperature is 92°F. The shape to be tested is shown below.
3. Find the Running Clearance fit category for the hole and shaft shown below.
4. Set up a sine bar (with 5 inches between cylinder centres) to provide an angle of 15°.
a) What height of gauge blocks is required?
b) Suggest an appropriate set of gauge blocks from an 81 piece set.
c) What is the actual angle of the sine bar?
d) If the room temperature is 95°F and the coefficient of expansion is .000001” per inch per °F, and the gauge blocks are calibrated to 68°F, what is the actual sine bar angle?
e) Suggest a new gauge block stack for the conditions in d).
5. If the scale below reads .48, label the bottom vernier scale.
6. List four different reasons that a material like cheese would not be good for gauge blocks.
7. When using a dial indicator, is parallax or the principle of alignment more significant? Explain your answer.
8. How can you verify that a standard square is 90°?
9. Design a GO/NO-GO gauge for a 5” by 7” square hole with tolerances of ±.1” on each dimension. Show the tolerances and dimensions for the gauges.
10. Write the values displayed on the vernier scales below.
1. If the thimble on a micrometer is made larger, does it affect the ‘radial arm’, or the ‘inclined plane’ principle?
12. When a comparator approaches a workpiece from one direction, it will read a different value than when it approaches from the other way. Explain why.
13. One type of fit is for Interchangeable Assemblies (it uses tolerances to ensure that parts can be made separately, but still fit together). What are the two other types of fits that were described in class? Describe why they are different.
14. A square hole has one dimension that will be checked with a GO-NOGO gauge set. The basic dimension is 2.005” ±0.003”. The gauge and hole are used in a room temperature of 105°F, but they should be accurate when at 60°F. The gauge coefficient of linear thermal expansion is 0.000001”, and the coefficient is 0.000002” for the material of the workpiece with the hole.
a) What sizes should the GO and NOGO gauges be?
b) Using the gauge block set shown below, list the gauge block stacks required.
15. A square is set up the two ways shown below, and a comparator is run from one end to the other. The resulting measurements result in the rises, or drops indicated. If the comparator is run over a total distance of 5” for both measurements, what is the angle of the squares A and B?
16. The hole shaft pair is assembled with an LN fit.
a) Draw the tolerance diagram.
b) Determine what the LN fit number is.
17. A sine bar will be used to give an angle of 82°35’
a) If the sine bar has 5” centres, what height will be needed?
b) Calculate the gauge block stack for the height in a).
c) What is the actual angle of the sine bar?
d) If the temperature in the room is 65°F at calibration, and 85°F at use, what change in angle does the sine bar have (coefficient of linear thermal expansion 0.000001 “/”°F for the sine bar, and 0.0000005 “/”°F for the gauge blocks)?
e) Could the sine bar be used with other instruments to improve accuracy?
18. Draw the number on the vernier scale below if the reading is 1.12
19. Parallax effects are more important than the principle of alignment for flow type pneumatic comparators - TRUE or FALSE
20. Draw GO/NO-GO gauges for the shaft below.
a) parallax errors where the scale is not parallel to the work.
b) change in the length of the scale due to a temperature change of 1°C.
c) reading with a scale that has a damaged end.
d) rounding off to the nearest division.
a) vernier scales are used for linear measurements only.
b) micrometer scales are used for linear measurements only.
c) micrometer scales make vernier scales more accurate.
a) the radial arm principle amplifies the rotation of a screw to a larger surface area and radial travel.
b) the inclined plane principle means that a small axial travel for a thread will be amplified to a much larger radial travel
c) the principle of alignment suggests that the dimension to be measured, and the measuring instrument should be aligned along the same axis.
a) a surface that can be used to measure flatness without other equipment.
b) can be used for measuring small angles without other equipment.
c) a surface that can be used for measuring large angles without other equipment.
a) are more accurate near 90°.
c) are used with angular gauge blocks.
a) dial indicators use the inclined plane principle.
b) dial indicators are a crude form of comparator.
c) the range of the dial indicator is generally less than standard comparators.
b) If the stack found in a) is increased in temperature from the ambient of 23°C to a higher temperature of 41°C, what is the new dimension and tolerance? (assume the coefficient of linear thermal expansion is 10-7K-1. (8%)
