1. Precision Measuring

2. Precision – How close together or repeatable the results are –A precise measuring instrument will give nearly the same result each time that it is used. Accuracy – How close a measurement is to the accepted value –For example, a balance loaded with a standard 100 g weight should read 100 g. If it doesn’t, then the balance is inaccurate. Precision measuring tools are needed for accuracy

3. Steel Rule Micrometer Tools for Precision Measuring

4. Digital Caliper Dial Caliper Tools for Precision Measuring

5. The dial caliper isa precision measuring instrument. The caliper’s blade graduations are in inches and tenths (.1) of an inch. Reading a Dial Caliper inch Each inch is broken into ten, for.1 of an inch. {

6. The caliper’s dial graduations are in thousandths (.001) of an inch. The reference edge keeps track of larger increments; the dial is for smaller increments. Reading a Dial Caliper

7. One full revolution of the pointer on the dial equals one hundred thousandths (.100).

8. Blade Inside Measuring Faces Outside Measuring Faces Dial Fine Adjustment Screw Dial Clamp Screw Clamp Screw Dial Caliper Parts

9. Step 1 Read inches from the blade 1 in. – 6 in. 2 Reading a Dial Caliper

10. Step 2 Read tenths of an inch from the blade Reading a Dial Caliper 1 in. – 6 in..0 in. -.9 in. 2 3

11. Step 3Read thousandths of an inch from the dial Reading a Dial Caliper 1 in. – 6 in..0 in.-.9 in..001 in.-.099 in. 2 3 2 8

12. Dial Calipers Measure Thickness or Outside Diameter

13. Using the dial caliper as an outside caliper

14. Dial Calipers Measure Thickness or Outside Diameter Inside Diameter or Space Width

15. Using the dial caliper as an inside caliper

16. Dial Calipers Measure Thickness or Outside Diameter Inside Diameter or Space Width Depth

17. Using the dial caliper as a depth gauge

18. Dial Calipers Measure Thickness or Outside Diameter Inside Diameter or Space Width Depth Step Distance

19. Discussion Questions List measurement tools… Steel RuleTape Measure Dial CaliperMeter Stick Explain which one of the tools listed would be best to use and why when measuring: –The hallway –Engineering Notebook –Pencil diameter –Height of your desk

20. Resetting the dial caliper to zero Begin by gently closing the calipers. Do not over tighten, close the jaws until they are touching Gently turn the glass dial until the indicator reads zero. Step 1 Step 2 Note the indicator is not on zero

21. Measuring with a dial caliper What is the reading on the dial caliper at the left? ?

22. Measuring with a dial caliper 1.000 One inch

23. 1.000.300 One inch three hundred Measuring with a dial caliper

24. 1.000.300 +.050 One inch three hundred fifty thousands Measuring with a dial caliper 1.350

25. Measuring with a dial caliper 1.000 One inch

26. Measuring with a dial caliper 1.000.800 One inch eight hundred

27. Measuring with a dial caliper 1.000.800 +.075 1.875 One inch eight hundred seventy five thousands

28. What is the reading on this caliper? Nine hundred and ninety thousands

29. What is the reading on this caliper? Two inch two hundred and sixty thousands

30. What is the reading on this caliper? Four inch one hundred twenty five thousands

31. Micrometer The thimble consists of a graduated scale that reads from 0-9. There are four marks between each number. Each mark signifies.025 (twenty five thousands).

32. Micrometer - sleeve The sleeve has a graduated scale that runs from 0-20 with 10 marks in between.

33. Reading the Micrometer There are four marks on the thimble. 4*.025 =.100 Zero marks on the sleeve. The micrometer reads.100 of an inch

34. Reading the Micrometer Two numbers on the thimble.200 There are almost three lines after the last whole number 2*.025 =.050 21 on the sleeve..271 or two hundred seventy one thousands

35. Steel rules

36. Steel Rules The top rule measures in fractional values The bottom rule measures in decimal values

37. Image Resources Microsoft, Inc. (2008). Clip Art. Retrieved October 10, 2008, from http://office.microsoft.com/en-us/clipart/default.aspx http://office.microsoft.com/en-us/clipart/default.aspx Wikimedia commons (2008). Retrieved October 15, 2008, from http://commons.wikimedia.org/wiki/ImageCaliper http://commons.wikimedia.org/wiki/ImageCaliper