Engineering recommendation report.

1. TCM359 Polished Recommendation Report Joe Legan
TCM 359 Recommendation Report
4/10/16
Joe Legan

2. TCM359 Polished Recommendation Report Joe Legan
Executive Summary
The purpose of this report is to recommend one of two designs of a lug wrench for use with an
all-terrain vehicle (ATV). The criteria used are cost, weight, strength and dimensions. Of the
four criteria, cost and strength are the most important. Design A has an advantage of requiring
fewer processes to manufacture as documented in the Dimensions section below. Design B has
advantages in all three other criteria, especially cost and strength. For this reason it is
recommended that Design B be put into production as it meets all the needs of the ATV
manufacturer.

3. TCM359 Polished Recommendation Report Joe Legan
Introduction
The purpose of this report is to recommend one of two different designs of a lug wrench for use
with an all-terrain vehicle (ATV). The goal of the design is to create a low cost and light weight
design that is suitable for manufacturing. Design A is a traditional style of lug wrench and can
be seen in the Appendix as Figure 1. Design B is a T-handle style that can be seen in the
Appendix as Figure 2. There are two possible solutions between the designs. The first solution is
an extended analysis of Design A followed by a probable change in dimensions to the tool. The
second solution is to proceed with lifecycle testing of Design B in preparation for production.
Problem
There are two possible designs for the lug wrench, only one can produced.
Scope
The four criteria provided for the design were that it had to be low cost, lightweight, be able to
withstand 70 pound applied force (strength), have a 3 inch stub shaft and a 12 inch lever arm
(dimensions).
Discussion
Cost
Design A has a mass of 0.61 kg and at a rate of 0.614USD/kg, each unit would cost $0.37 in
material to produce. Design B has a mass of 0.41 kg and at the same rate would cost $0.25 for
each unit produced in material cost. This is a savings of $120.00 per 1,000 units produced. The
exact mass properties can be seen in the appendix. Cost is of some concern as usual but it is not
the most critical criteria. This criteria has a moderate weighting.
Weight
Design A has a weight of 1.34 pounds while Design B has a weight of 0.91 pounds. Design B has
a weight savings of just under 68%. Weight of the tool is considered as it could potentially
detract from the performance of the ATV. No special weighting is required for this criteria.

4. TCM359 Polished Recommendation Report Joe Legan
Strength
Analysis reveals that Design A will fail under the applied 70 pound force. Design B will not fail.
Design A has a Factor of Safety (FOS) of 0.91 while Design B has a FOS of 10 at the lowest point
(Legan/MET310, 2016, p. 5). As the manufacturer of the ATV strives to produce a quality product,
they have great concern that the tools they include with their product be of sufficient strength
to perform the task required. This criteria is heavily weighted.
Dimensions
Both designs have the required dimensions of a 12 inch lever arm and a 3 inch stub shaft.
However Design B has a smaller surface area by 67% making packaging for it easier within the
confines of the ATV. Design A can be cast as a single piece requiring no special machining.
Design B can be cast as one piece or welded from two independent pieces. No special weighting
is required for this criteria.
Table of Criterion Advantage by Design
Criterion Design A Design B
Cost ($/unit) $0.34 $0.25
Weight (lbs) 1.34 0.91
Strength (FOS) 0.91 10.0+
Dimensions
(Surface area sq. inches)
33.86 22.75
Conclusion
Summary
This study evaluated two designs for a lug wrench for use with an all-terrain vehicle based upon
the criteria of cost, weight, strength and dimensions. Design B has advantages in both cost and
strength, the heavily weighted criteria. Design A can be manufactured in few processes than
Design B.

5. TCM359 Polished Recommendation Report Joe Legan
Conclusion
Design B has more advantages than A in all respects save the amount of steps to manufacture.
Given that tool must meet the criteria of the customer while creating a profit for us the
manufacturer, it appears that Design B will be more suitable design with its advantages over
Design A Due to these advantages it is recommended that Design B be put into process for
lifecycle testing in preparation for production.

6. TCM359 Polished Recommendation Report Joe Legan
References
Legan/MET 310, J. F. (2016). Simulation of modified lug wrench (1). Indianapolis, IN:
SolidWorks Simulation.

7. TCM359 Polished Recommendation Report Joe Legan
Appendix
Figure 1

8. TCM359 Polished Recommendation Report Joe Legan
Figure 2
Design A Mass Properties
Mass properties of Project 1 Final Attempt
Configuration: Default
Coordinate system: -- default --
Density = 0.13 kilograms per cubic inch
Mass = 0.61 kilograms
Volume = 4.76 cubic inches
Surface area = 33.86 square inches

9. TCM359 Polished Recommendation Report Joe Legan
Center of mass: (inches)
X = 4.65
Y = 0.51
Z = 0.00
Principal axes of inertia and principal moments of inertia: (kilograms * square inches)
Taken at the center of mass.
Ix = ( 0.99, -0.16, 0.00) Px = 0.40
Iy = ( 0.16, 0.99, 0.00) Py = 9.70
Iz = ( 0.00, 0.00, 1.00) Pz = 10.07
Moments of inertia: ( kilograms * square inches )
Taken at the center of mass and aligned with the output coordinate system.
Lxx = 0.63 Lxy = -1.43 Lxz = 0.00
Lyx = -1.43 Lyy = 9.47 Lyz = 0.00
Lzx = 0.00 Lzy = 0.00 Lzz = 10.07
Moments of inertia: ( kilograms * square inches )
Taken at the output coordinate system.
Ixx = 0.78 Ixy = 0.00 Ixz = 0.00
Iyx = 0.00 Iyy = 22.61 Iyz = 0.00
Izx = 0.00 Izy = 0.00 Izz = 23.36
Design B Mass Properites
Mass properties of Modified Lug Wrench
Configuration: Default
Coordinate system: -- default --
Density = 0.13 kilograms per cubic inch
Mass = 0.41 kilograms
Volume = 3.27 cubic inches
Surface area = 22.75 square inches

10. TCM359 Polished Recommendation Report Joe Legan
Center of mass: ( inches )
X = 0.00
Y = 0.00
Z = 0.97
Principal axes of inertia and principal moments of inertia: ( kilograms * square inches )
Taken at the center of mass.
Ix = ( 1.00, 0.00, 0.00) Px = 0.71
Iy = ( 0.00, 0.00, -1.00) Py = 0.72
Iz = ( 0.00, 1.00, 0.00) Pz = 1.40
Moments of inertia: ( kilograms * square inches )
Taken at the center of mass and aligned with the output coordinate system.
Lxx = 0.71 Lxy = 0.00 Lxz = 0.00
Lyx = 0.00 Lyy = 1.40 Lyz = 0.00
Lzx = 0.00 Lzy = 0.00 Lzz = 0.72
Moments of inertia: ( kilograms * square inches )
Taken at the output coordinate system.
Ixx = 1.10 Ixy = 0.00 Ixz = 0.00
Iyx = 0.00 Iyy = 1.79 Iyz = 0.00
Izx = 0.00 Izy = 0.00 Izz = 0.72