LABORATORY SUPPLEMENT
Version 1.0
6/4/96
Written by: Lynn Seery
Asst. Professor QET
Sinclair Community College
Dayton, OH 45402
lseery@sinclair.edu
This module is a laboratory supplement created for the multi-media
challenge grant awarded to the QET Department at Sinclair Community
College. Its objectives are 1) to introduce participants to the
theory, equipment, and techniques used in vernier metrology and
2) to provide a context for a more sophisticated use of vernier
instruments in further studies and in the workplace.
The module achieves its objectives primarily through a series
of three laboratory exercises using a vernier height gage, caliper,
and micrometer to measure some gage blocks to establish the accuracy
and calibration of the system. The participant then completes
the activity by measuring a machined part with the three different
vernier instruments and comparing the results. Significant tools
and techniques of vernier measurement are introduced through the
lab exercises and supplemental reading. Readings are from the
text used in the QET Metrology series (QET 111, 112, 113 etc.)
Fundamentals of Dimensional Metrology by Ted Busch.
Reading Assignment : Ted Busch
Learning Task #1 : Calibration
Learning Task #2 : Measurement with Verniers
Sample Letter of Transmittal
Sample Title Sheet
Typical Format for Lab Report
You are not expected to have any prior experience in measuring
with vernier instruments to participate in this introductory exercise.
You should have a good foundation in basic mathematics, science,
and communication skills. Does this description fit you? Welcome
to the lab!
When you have completed this set of activities you, should find that you are able to:
1. Calibrate a vernier micrometer, caliper, and height gage using a micrometer.
2. Use these same vernier instruments to measure the dimensions of sample parts.
3. Prepare a professional laboratory report based on divisional guidelines.
4. Evaluate the possible causes of differences between your instrument readings and other readings on the same part.
Take a few moments here to evaluate how these skills will serve
your career goals:
_____ Immediate goals (credit towards degree/certificate , on-the-job
problem solving)
_____ Midrange goals ( employment opportunities)
_____ Long-term goals (career advancement,achievements)
1=Very important, 2= Fairly important, 3=Less important
What distinguishes “precision “ from “non-precision”
instruments? In previous labs you have worked with measuring instruments
that were limited by your senses of sight and feel. Now, thanks
to a system of scales invented by Pierre Vernier ( aka,Vern) in
1631, our ability to discriminate has been enhanced. This system
enables us to more carefully discern the last decimal value via
lining-up two marks on adjacent scales . This technique is a form
of amplification ( the answer to the opening question).
Although digital readout instruments and dial calipers are rapidly
replacing vernier instruments in the workplace, the principles
of vernier instruments are basic to metrology; and anyone who
can measure with vernier instruments can use the digital and dial
versions with equal or better reliability.
In this lab you will learn and practice these techniques, and
gain a new appreciation for the lost world of ANALOG!
Before proceeding further with this lab, you should have read through chapter 6 in Fundamentals of Dimensional Metrology by Ted Busch, 2nd edition. Additionally, if you are not familiar with the use of gage blocks and calibration techniques, please read chapters 9 and 13 respectively.
Purpose: To insure the accuracy , get practice using the instruments,
and get immediate feedback on the quality of our measurement systems;
we will measure several gage blocks with vernier micrometer, vernier
height gage, and vernier caliper.
Procedure:
1. Pick one gage block from each of the four series (0.1001”-0.1009”, 0.101” - 0.149”, 0.050” - 0.950”, and 1.000” - 4.000”).
2. Measure the four gage blocks with each of the three instruments and record the results on the data sheet provided .
3. Compare your results and determine the cause(s) of any differences greater than 0.002 inches.
4. If you are unable to achieve the desired accuracy, please return the instrument(s) to the lab technician for recalibration.
Purpose: To simulate the measurement of “manufactured “parts and gain further experience using vernier instruments.
Procedure:
1.Chose a slotted block from top drawer in the QET Lab (room 5021).
2. Record the block I.D. # on your data sheet.
3. Measure the dimensions (A,B,C, D, &E) as indicated on the data sheet.
4. Again compare your readings and determine the causes of any differences greater than 0.002”.
5. Compare your results with the dimensions on the Master Sheet for your block #, and again determine the causes of any differences greater than 0.002”
1. Describe the procedures for using vernier micrometers, calipers,
and height gages.
2. Compare and contrast the precision, accuracy, and use of
these instruments.
1. Examine the following representations of vernier measuring instruments, and record your readings in the space below the drawings.
2. Compare your readings with the values on the answer sheet (available
from the Lab Technician).
3. Describe your level of confidence in your measurement with
vernier instruments.
Back
to the table of contents
I. Data Sheet for Learning Task #1:Calibration
Gage Vernier Vernier Vernier Measurement Block Micrometer Caliper Height Range Size Measurement Measurement Measurement ------------------------------------------------------------------------------------------------------------------surmount | | | | | | | | | | | | | | | |
II. Slotted Block Measurement
Select one of the slotted blocks and record its number. Using a vernier micrometer, vernier caliper,
and a vernier, and vernier height gage measure each of the part features to the nearest 0.001 inch
and record your measurements.
Part Number_____________
_____________________________________________________________________________________
Feature | Measurements
Vernier Vernier Vernier Measurement
____________Micrometer_________Caliper_________Ht.Gage________Range_______________
A
B
C
D
E
F
III. Steps in reading verniers and suggestions.
Steps for Using the Vernier Caliper
Suggestions for Reliable Height Gage Measurement
Ted Busch, Fundamentals of Dimensional Metrology, 2nd edition, ( Albany, NY: Delmar Publishers, 1989) pp. 93-369.