Course Title:
Small Engine Technology
Lesson Title:
Reading and Using the Micrometer
TEKS Addressed in Lesson: 130.400 http://ritter.tea.state.tx.us/rules/tac/chapter130/ch130p.html
130.400c8D
130.400c8E
The student demonstrates the technical knowledge and skills for small engine technology:
The student will identify and safely use small engine measuring tools; and safely use tools used in the
operation, maintenance, and repair of two- and four-cycle engines.
Lesson Objectives: The student(s) will be able to:
1.
2.
3.
4.
Identify the various types of micrometers and their parts;
Select the appropriate micrometer as per its size and use;
Read and use the micrometer proficiently to measure; and
Check tolerances of finished machined parts.
Tools and Equipment
Dry-erase board or flip chart & markers
PowerPoint slides – laptop and LCD projector
Computer with Internet access, if available
0 to 1" and 1 to 2" outside micrometer calipers, other types (inside, depth and thread mikes) if possible;
several pieces of various ground flat bar and round bar.
Teaching Aids: PowerPoint Slides: VI-A-3(PP) Figures 1-7
Information Sheet, VI-A-3(IS) "Reading and Using the Micrometer"
Assignment Sheet, VI-A-3(AS) "Reading and Using the Micrometer"
Key Terms / Vocabulary
Anvil
Barrel
Caliper
Frame
Lock nut
Micrometer
Ratchet stop
Spindle
Thimble
Units
Inches
Tenths
Hundredths
Thousandths
Ten-thousandths
Interest Approach / Anticipatory Set
The word "Micrometer" is derived from two Greek words. Micro, meaning small or little, and Meter,
meaning a measure. The decimal micrometer is based on the decimal inch, and some read to one tenthousandth of an inch. The most commonly used precision measuring device in industry today (for linear
dimensions) is the micrometer which measures accurately to one-thousandth of an inch. This micrometer is
used extensively in the mechanical repair industry for measuring and checking tolerance or wear on such
things as shaft diameters and other cylindrically machined parts.
The decimal micrometer is the most commonly used precision measuring instrument in industry today. The
standard micrometer measures accurately to one-thousandth of an inch.
The mechanical repair industry has many uses for the micrometer, among which the most prevalent is
checking size, tolerance, and wear of closely machined parts such as shafts, cylinders, and bearings.
The student of mechanical repair trades must become adept at using the micrometer to fulfill requirements
demanded of this industry. Today we are going to learn how to use and read the micrometer.
Teaching Plan and Strategy / Presentation of New Material
Show Slide Figure #1
1. Present general information about the micrometer.
Show Slide Figure #1
2. Discuss the types and sizes of micrometers.
3. Present the parts of outside micrometer.
4. Teach students how to read the micrometer.
5. Explain sequence of reading calibrations.
Show Slide Figure #2
Note: Slide will reveal covered readings.
Show Slide Figure #3
Note: Slide will reveal covered readings.
Show Slide Figure #4
Note: Slide will reveal covered readings.
6. Model using the micrometer properly.
Show Slide Figure #5
7. Demonstrate checking for accuracy.
8. Present procedures for care and storage of the micrometer.
Activity / Application / Student Engagement / Laboratory
Reading Assignment:
Information Sheet, VI-A-3(IS) "Reading and Using the Micrometer"
Written Assignment:
Assignment Sheet, VI-A-3(AS) "Reading and Using the Micrometer"
U-shaped crescent
1. The general shape of the frame of outside micrometer calipers is ______.
40
2. The number of threads per inch on the spindle is ______.
Decimal inches
3. Micrometers are calibrated to measure in ______.
1/10,000"
4. Vernier mikes will measure accurately to ______.
Barrel
5. The longitudinal calibration and index line are located on the ______.
T.P.I.
6. Thread mikes range in one inch intervals and by a range of ______.
Ratchet
7. The part which prevents the frame from being sprung from undue pressure
by the threads is ______.
Anvil
8. A hardened button insert at one end of the frame is ______.
1 inch
9. The travel or adjustment of mikes is generally ______.
Measure
10. The Greek word "Meter", means ______.
2-3" outside
11. To check a shaft diameter of 2.248" would require a ______ ______
micrometer.
1. Have students list on chalkboard/whiteboard/flip chart points of care and use, and briefly explain why.
2. Class to form small groups and practice miking (measuring) objects supplied by the instructor. Groups
write down answers and compare at end of practice.
3. Class to write a short paragraph explaining why micrometer threads are 40 T.P.I.
Evaluation / Summary
Show Slide Figure #6
Pictorial Recall Test: Parts of Micrometer Caliper
1.
2.
3.
4.
5.
6.
7.
8.
Ratchet stop
Thimble
Barrel
Lock nut
Frame
Spindle
Anvil
Cut out frame
Show Slide Figure #7
Pictorial Recall Test: Reading the Micrometer
1. .400
2. .025
3. .333
4. .555
SUMMARY
The word "micrometer" is derived from two Greek words. Micro, meaning small or fine, and Meter,
meaning measure. The Micrometer (nickname, mikes) is a precision measuring instrument which measures
accurately to a thousandth part of an inch.
There are several types; outside, inside, depth and thread mikes, all having the same or similar working
parts and are read in a like fashion. Most have one inch of travel or adjustment and come in sizes of one
inch increments.
The micrometer is composed of a frame (u-shaped on outside mikes) with an anvil at one end and a barrel at
the opposite end. The barrel contains internal threads (40 T.P.I.) and outside a longitudinal index line and
calibrations. The spindle assembly is composed of the spindle, which has mating threads (40 T.P.I.) to
engage with barrel and affect travel of the assembly. The spindle is affixed to the thimble by a thimble cap,
which also houses a ratchet stop. The thimble is a hollow tube beveled at the end opposite the cap and
calibrated, circularly, in twenty-five equal parts. The assembly travels as a unit by turning the thimble.
The micrometer caliper is a precision measuring instrument. The proper use and care of this instrument will
insure years of dependable service. Care should be given in handling not to bump or drop the mikes, and in
storage to be separated from heavier tools. Measurements should be made with a light touch and each
measurement double checked for accuracy and reading.
In reading the mikes, each large longitudinal calibration on the barrel is 1/10" or .100" - read only those
completely visible. To this, add each small longitudinal calibration which equals 1/40" or .025" - again, read
only those completely visible. Last, read the circular calibration on the barrel nearest the index line and the
total of the reading will result in the nearest decimal fraction of an inch of the object being measured.
References / Additional Materials / Extended Learning Opportunities / Enrichment
https://www.google.com/search?q=micrometer&client=firefox-a&rls=org.mozilla:enUS:official&channel=sb&biw=1233&bih=724&tbm=isch&tbo=u&source=univ&sa=X&ei=o1JJVJ_MN8HpggTC
04DQCg&sqi=2&ved=0CEYQsAQ
http://www.youtube.com/watch?v=i_jygJkJujE
http://www.grainger.com/category/micrometers/measuring-and-layout-tools/hand-tools/ecatalog/N-961
http://www.wikihow.com/Use-and-Read-an-Outside-Micrometer
College & Career Readiness Standards: http://www.thecb.state.tx.us/collegereadiness/crs.pdf
ENGLISH/LANGUAGE ARTS STANDARDS
I. Writing – A 1 2 3 4 5
II. Reading – A 1 2 3 4 5 B 1
III. Speaking –B 1 2
IV. Listening – A 1 2 3 B 1 2 3
MATHEMATICS STANDARDS
I. Numeric Reasoning – A 1 2 B 1 C 1
II. Algebraic Reasoning – A 1 B 1 C 1
IV. Measurement Reasoning – A 1 B 1 2
VIII. Problem Solving and Reasoning – A 1 2 3 4 5
IX. Communication and Representation – A 1 2 3 C 1 2 3
X. Connections – A 1 2 B 1 2 3
CROSS-DISCIPLINARY STANDARDS
I. Key Cognitive Skills –C 1 2 3 D 1 2 3 4 E 1 2
Revised by:
CDC Custom Development Co., LLC
for Texas A&M University.
Copyright © 2014 Texas Education Agency