DiGiannoMeasurment

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Mechanical Engineering

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Jan 9, 2024

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Mechanical Engineering Laboratory New Jersey Institute of Technology Report Submitted by Michael F. DiGianno Experiment No. 5 Date Performed 10/17-24/23 Date Submitted 10/31/23 Course & Section ME215-101 Instructor Naruemon Suwattananont Measurement Experiment Title Performed by Group 101b With TA Md Sojib Kaisar Group Members Michael D Bauly S Yahia Elmanier Marta D Stephen M Jonathan G Braeden G

Table of Contents Abstract 3 Introduction 3 Objectives 3 Background and importance 3 Procedure 4 Original Data Sheet 5 Results and Calculations 6 Discussion 12 Conclusion 12 Questions and Answers 13 Appendix A 14 2

Abstract This is the lab report for experiment four, known as the measurement lab. This lab is designed to introduce students to various measurement tools and techniques. It was split into two weeks, each one focusing on different tools and problems. Students used the tools to verify different dimensions and tolerances on specimens provided. The students found how accurate the tools were and the difficulty associated with operating analog measurement devices. Introduction Digital measurement tools aren't always available, sometimes there are limited resources or no electricity. Understanding how to use these versions is important for when the situation arises. Depending on a person's field they will likely encounter GD&T. It’s a common standard that is used to define dimensions and tolerances in mechanical drawings. Objectives Students participating in this lab should be able to develop an understanding of the measurement tools provided. They should be able to use them effectively and understand what situations call for each tool. Students should also be able to identify the general callouts and symbols of GD&T. They should be able to measure and verify these specifications. Background The history of GD&T is quite recent. It was pioneered by Stanley Parker in the 1940’s. “He had worked on problems that Britain was faced with complications in fabricated material compatibility and interchangeability.” (Acharya 1992). That said the tools used predate this significantly. Procedure This lab is split into two weeks, although the general procedure remains similar for both weeks. Students are introduced to a set of tools each week. These were a vernier caliper, micrometer, pitch gauge and optical comparator for week 1. These were dial indicators and protractor for week 2. then given specimens that they must use the tools on. In week 1 they were asked to specify the dimensions of objects. In week 2 they were asked to verify tolerances and dimensions. 3

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Original Data Sheet 4

Results and Calculations 5

4threads / 0.3604in= 11.09 threads per inch 6

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Discussion The primary objective of this lab was to familiarize ourselves with both measurement tools and GD&T. It started rocky as the vernier caliper and micrometer are impressively unintuitive tools to use. That said with effort, the group learned. The optical comparator and pitch gauge are simple and easy to use. There was some general confusion between the professor and the rest of the class on how the optical comparator should be used, but was resolved quickly. GD&T callouts were easy enough for the group to understand as there is a table of them provided in the lab background. For the first week of the lab, there are no expected numbers that were made privy to us. We successfully measured all dimensions that were asked of the group. So, while our papers were signed off on, there were no expected values for us to draw deviations or percent error from. On the other hand The second week had us working backwards. We were given tolerances and dimensional callouts for two pieces. As we were given the expected values it is to be expected that we would deviate. Some of the callouts were correct while others did not meet tolerances. Some are even visible to the eye on close inspection. There is definitely some variation in our answers. No measurement is perfect, and some group members were using these tools for the first time. This is paired with the fact that each specimen was handled by different lab mates creates unreliability in the measurements taken. This can be compounded with us using a calculator for several measurements that means that rounding took place. I believe that despite this, our numbers are still fairly accurate and are only to be taken with a small assumption of error. Conclusion In conclusion, we have familiarized ourselves with the basic tools and techniques for analyzing various dimensions and geometries. We can confidently use said tools when asked to verify GD&T callouts. We understand the general GD&T symbols and their meanings. That said, we can't help but feel that some of these tools have become outdated to the accuracy and ease of use of their modern or digital counterparts. 10

Questions and Answers 1. (A) 3.285 (B) 1.546 (C) 2.816 (D) 3.568 2. Clearance refers to the maximum hole size and minimum shaft size, interference fit is the inverse 3. It’s the difference between the upper and lower limits 4. You could compare it with a pre calibrated micrometer, or a standard gage/slip gague 5. Ts= 1+.005-(1+0.003)=1.005-1.003=0.002 Tbo=- 3+0.0-(3-0.003) = 0.003 Tbi=1+0.002-1=0.002 Tbf=3+0.004-3=0.004 Abs=1+0.002-(1+0.003)=-0.001 Abf=3+0.004-(3-0.003)=0.007 6. Its the difference between the maximum shaft size and minimum hole size 7. Mxc=0.001+0.004+0.003=0.08 Mmc=1-0.001=0.999 Udh=1.004-1=0.004 Uds=1-1=0 Ldh=0.999-1=-0.001 Ldh=0.996-1=-0.004 Appendix A. Acharya, Srihari G., "Design for productivity using GD&T" (1992). Theses. 1275. https://digitalcommons.njit.edu/theses/1275 11