MECH/ESSE 2401 E NGINEERING G RAPHICS & CAD M ODELING – C OMPUTER

A IDED D ESIGN P ROJECT

Team Members: Ameer Rashid - 213766704 , Akash Oommen - 213725437 , Garen Keleshian - 213874359

Executive Summary

Presently, we have crafted a miniature hammer for a co-requisite course, MECH 2501 using the

University’s machine shop, which is situated in Bergeron. The hammer lacks flair and so, we had

been tasked to form design teams of exactly three students to develop detailed CAD models and

working drawings of a case with a locking mechanism for the hammer head using SolidWorks.

The term project was divided into five main tasks. Task 1 required us to create a solid model

(assembly) of the miniature hammer whose dimensions and geometries were to strictly follow

the engineering drawings provided by Prof. Alex Czekanski (Director of MECH 2501) by first

modeling the parts (handle, head, inserts) of the hammer using SolidWorks. In addition, we were

to create an engineering drawing of the hammer assembly using the standards learned in MECH

2401. Task 2 required each team member to prepare 10 free-hand sketches of the case (each

sketch was distinct but not necessarily practical). Thereafter, a team decision was made in order

to select four designs out of 30 possible designs taking into consideration several factors including

difficulty of modeling, fit, style, locking mechanism and hammer head dimensions and tolerances.

Then those four designs (Sketch # 10, 12, 18 and 24) were compared taking into consideration

the aforementioned criteria. Out of those four designs Sketch # 10 was chosen as a case for the

hammer head because of its relatively simple yet stylish design, easy to model locking mechanism

and close resemblance to the hammer head’s geometry. Task 3 required us to construct a solid

model (assembly) of the hammer head case using SolidWorks. In addition, we also had to create

an engineering drawing of the case assembly. To test if the case fits and its locking mechanism

works, we were to construct an assembly of the full hammer with the case applied in SolidWorks

using mates. Task 4 (optional) required us to use additive manufacturing techniques to 3-D print

the hammer head case by first preparing an .STL file(s) of the case and then using MakerBot to

print the case. Task 5 was to write a report on the chosen case design. This report will feature a

detailed table of contents, provide an in-depth discussion of the ideation process and rationale

for the design selection by comparing the selected case design to three other relatively good

designs, a thorough discussion of the final case design along with appropriate drawings and

complete step-by-step instructions of the modeling procedure using SolidWorks and a

justification for the case dimensions. The report will also feature a conclusion summarizing the

reasons Sketch # 10 was chosen amidst all others along with a restatement of the primary

objective(s) of the project and its learning outcomes. Lastly, the report will feature an appendix

which provides an in-depth overview of the role/contributions of each team member throughout

the term project, all ideation sketches completed in Task 2, all engineering drawings of individual

parts and assemblies, and any other additional information that would help improve the clarity

of this final report.

TABLE OF CONTENTS Introduction

Discussion of the Ideation Process and the Rationale for Design Selection

Discussion of the Final Design with Appropriate Drawings

Concluding Remarks

Appendices

• All engineering drawings of individual parts and assembly

• Any other additional information that would help to improve the clarity of the final

report.

• Role/contribution of each member in the term project

Introduction

This term project served two purposes, the first was to design a case for a miniature hammer

crafted in the co-requisite course MECH 2501 as it lacked flair. The second purpose was to

emphasize the importance of planning, the development of modeling strategies, the

consideration of tolerances and the spirit of teamwork. The chosen case had to meet several

criteria, three of them being that it had to tightly/closely fit the hammer head, have a functional

locking mechanism and be relative easy to model in SolidWorks. Before a final design was

selected each team member was required to prepare 10 free-hand sketches of the case (each

sketch being distinct but not necessarily practical). Thereafter, a team decision was made in order

to select four designs out of 30 possible designs taking into consideration the aforementioned

criteria and others such as style and hammer head dimensions and tolerances. These four designs

were compared and from them one was selected as the final case design. We chose Sketch # 10

because it met all the aforementioned criteria. To test if the final case design fit the hammer head

and its locking mechanism worked it was modeled and then assembled using SolidWorks and

applied to a full hammer assembly which consisted of the individual parts (handle, head and two

inserts). This report will feature a detailed table of contents, provide an in-depth discussion of

the ideation process and rationale for the design selection, a thorough discussion of the final case

design along with appropriate drawings and complete step-by-step instructions of the modeling

procedure using SolidWorks and a justification for the case dimensions and tolerance(s). The

report will also feature a conclusion summarizing the reasons Sketch # 10 was chosen amidst all

others along with a restatement of the primary objective(s) of the project and its learning

outcomes. Lastly, the report will feature an appendix which provides an in-depth overview of the

role/contributions of each team member throughout the term project, all ideation sketches

completed in Task 2, all engineering drawings of individual parts and assemblies, and any other

additional information that would help improve the clarity of this final report.

Discussion of the Ideation Process and the Rationale for Design

Selection

As stated before, the primary objective of the term project was to add flair to the miniature

hammer created in the co-requisite course MECH 2501 by designing a case for the hammer

head (not the entire hammer). Task 2 required each team member to prepare 10 free-hand

sketches of the case (each sketch being distinct but not necessarily practical). When sketching

each member knew that the case had to be one that tightly/closely fit the hammer head while

being durable and easy to model in SolidWorks. Thus, most team members used basic shapes

(rectangle, hexagon, and cylinder) as the base (portion in which the hammer head would rest)

in their sketches because initially, before adding the 15 revolved cuts to the hammer head,

it was a rectangle and even afterwards still retains those flat rectangular surfaces. Moreover,

these shapes would provide a matching fit for the hammer head thereby allowing a secure fit

and would be easiest to model in SolidWorks. As for the hammer head inserts, most sketches

accounted for those by adding circular or square extrusions on either side of the base because

the inserts themselves were circular, so using a square or cylindrical extrusion would provide

the closest and most secure fit for the inserts while being relatively easy to incorporate to the

solid model for the hammer head’s base. Many case sketches were such that they required two

halves for the case. This was to allow for ease of assembly without necessarily dissembling the

hammer (i.e. first removing the handle and then enclosing the hammer head in the case).

Furthermore, a lot of sketches used simple locking mechanisms e.g. a hinge and locks, velcro

straps (like those used to close an umbrella), push buttons, zippers and combinations of these.

After each member prepared his 10 free-hand sketches for the hammer head case, a team

decision was made in order to select four designs out of 30 possible designs taking into

consideration several factors including difficulty of modeling, fit, style, locking mechanism and

hammer head dimensions and tolerances. We chose Sketches # 10, 12, 18 and 24. Then each of

these sketches were compared (pros and cons) using the aforementioned criteria. Sketch # 10

(refer to appendices page 15) consisted of two identical pieces labeled piece 1 and piece 2

respectively. Both piece 1 and piece 2 consisted of a rectangular base with extruded half arcs in

which the hammer head plus inserts (i.e. the hammer head with the inserts screwed in) would

rest. Piece 1 had a hole for the handle while piece 2 did not. Both pieces had a wall of thickness

Z. However, on the top of the walls of piece 1, a groove pattern was made. This groove of depth

X was created as part of the locking mechanism for this design. On the top of the walls of piece

2, an extrusion of height Y was created because this extruded part would fit inside the grooves

in the walls of piece 1. Sketch # 10 utilized a tongue and joint locking mechanism. Sketch # 12

(refer to appendices page 16) consisted of a cylinder that was threaded towards the top so it

could be opened or closed with circular lid (similar to a medicine bottle). Sketch # 12 had a hole

that was cut in the bottom of the cylinder for the hammer handle. Sketch # 18 (refer to

appendices page 19) consisted of a rectangular box with a lid on top that would serve as the

locking mechanism. It also had a hole in the bottom for the handle. Sketch # 24 (refer to

appendices page 21) consisted of a double-arrow shaped base that was extruded some height

and turned on its side. It had a hole in one of its side faces to allow for the insertion of the

hammer handle. Sketch # 12 was not considered because of its locking mechanism (medicine

bottle style) which would prevent the case from sitting level with a flat surface. It would also

look strange from one end because the lock portion (i.e. the lid) would be larger than the closed

end. Sketch # 18 was not considered because its design was far too simple (shoe box). Also, its

locking mechanism was not very secure, if the hammer were held upside down the lid would fall

off. Sketch # 24 was not considered because it lacked a clear locking mechanism and the

triangular portion where the inserts would be situated would not provide a tight fit. Thus, out of

those four sketches, Sketch # 10 was chosen as a case for the hammer head because of its

relatively simple yet stylish design, easy to model locking mechanism and close resemblance to

the hammer head’s geometry.

Discussion of the Final Design with Appropriate Drawings

Sketch # 10 was chosen as a case for the hammer head because of its relatively simple yet stylish

design, easy to model locking mechanism and close resemblance to the hammer head’s

geometry. Using SolidWorks, the case was dimensioned such that the interior of the base

(rectangle) matched the maximum exterior dimension of the hammer head (45.2 mm X 20.2 mm).

This sketch was then extruded 2 mm in height to add thickness to the base. Then the base’s

exterior dimensions were chosen by drawing a rectangle around the interior base sketch which

was 2 mm greater in length and width in every direction than the length and width of its interior

sketch i.e 49.2 mm X 24.2 mm. The exterior base sketch was then extruded 2 mm in the

downward direction and 10.2 mm in the upward direction. The 2 mm extrusion in the downward

direction was to ensure that the exterior base sketch was at the same height as the interior base

sketch before being extruded a further 10.2 mm in the upward direction. As for the 10.2 mm

extrusion in the upward direction, it was to account for the maximum half way height dimension

of the actual hammer head. Moreover, by extruding the exterior base sketch, a wall of 2 mm

thickness was created around the interior base sketch of 45.2 mm X 20.2 mm. A thickness of 2

mm was chosen as it was necessary to create the locking mechanism for this design. Then a circle

of diameter 19.2 mm was drawn on one of the exterior (24.2 mm) faces of the rectangular base

and extruded 2 mm inwards and 10.2 mm outwards to create the portion of the case where the

insert would rest. Thereafter, a tangent arc of radius 11.1 mm was drawn on the bottom portion

of the circular extrusion by drawing a line of length 1.5 mm from each center-point edge of the

circular extrusion’s face and then connected by a 19.2 mm line drawn through the center of the

circular extrusions face. This arc was then extruded 2 mm outwards to account for the thickness

of the circular portion of the case where the insert would rest and 10.2 mm inwards (i.e. up to

the wall of the exterior base extrusion). Afterwards, a circle of diameter 19.2 mm was drawn

overlapping the previously extruded 19.2 mm circle. Then the extruded cut feature was used on

the overlapping circle (extruding inwards at 12.2) to remove the previously extruded 19.2 mm

circle. As a result, a half circle shape (tangent arc that was extruded 2 mm beyond the extrusion

point of the 19.2 mm diameter circle) was left. This half circle was created because the design for

this case involved two identical parts. Thus, when the two parts were joined a full circle which

would enclose the inserts was made. Now, the same procedure was applied to the other exterior

face of the base to make a portion to secure the second hammer insert. On the top face of the

walls a groove (refer to drawing 1) was made which was 2 mm deep and of varying thickness from

the center line of the walls. The thickness varied because the interior and exterior diameters of

the circular extrusions did not match with the interior and exterior lengths of the base walls upon

which they were constructed. Lastly, a circle of diameter 18.6 mm was drawn on the bottom

interior face of the rectangular base from the middle (22.6 mm) and cut using extruded cut. A

hole of 18.6 mm was created so that this portion of the case could simply slide through the

hammer handle (which has a maximum diameter of 18.5 ± 0.2 mm) without the need to

disassemble the entire hammer and then be sealed by the other identical half. Then a new part

file was made and the exact same procedures were used to construct the other identical half of

the first case piece. The only difference with the second case piece was that instead of extruded

cutting the groove pattern which was drawn on the top of the walls; it was extruded upwards by

2 mm from the face of the walls (refer to drawing 2). This was to complete the locking mechanism

for the case. The 2 mm extrusion would fit into the groove created on the previous piece thereby

locking the case. The hammer head measures 45 ± 0.2 mm along its length and 20 ± 0.1 mm

along its width and height. The half way height of the head measures 10 ± 0.2 mm. The inserts

measure 10 ± 0.2 mm (the threaded 10 mm portion is ignored here because it will fit inside the

hammer head). The major diameter of the inserts is 19 mm (ignoring the 8 mm diameter of the

threaded portion). The dimensions for the interior base and interior portion for the inserts were

all 0.2 mm greater than their actual part dimensions. This was to ensure a fairly tight/close fit,

had the interior dimensions been the same as the hammer head and insert assembly it may not

have fit/resulted in interference. The base thickness was chosen to be 2 mm to ensure the case

would be durable when printed. A tolerance of − 0.1 mm was selected for all

features/dimensions of the case as this would still allow all case feature dimensions to be greater

than the hammer head dimensions, which means the hammer head would still fit, only a little

tighter.

Hammer Head Case Engineering Drawing # 1:

Hammer Head Case Engineering Drawing # 2:

Conclusion

The primary objective of this term project was to create a case for the miniature hammer

created in the co-requisite course MECH 2501 to add some flair. The case had to tightly/closely

fit the hammer head while being durable. The ideation process required each team member to

prepare 10 free-hand sketches of the case (each sketch was distinct but not necessarily

practical). Thereafter, a team decision was made in order to select four designs out of 30

possible designs taking into consideration several factors including difficulty of modeling, fit,

style, locking mechanism and hammer head dimensions and tolerances. We chose sketches #.

These sketches were compared (pros and cons) using the aforementioned criteria. Of those

four sketches Sketch # 10 was chosen as a case for the hammer head because of its relatively

simple yet stylish design, easy to model locking mechanism and close resemblance to the

hammer head’s geometry. The case had a rectangular base to fit the hammer head because

initially, the hammer head was a rectangle before the 15° revolved cuts and even after the cuts

it still had mostly flat rectangular faces. As a result the case would tightly fit the hammer head.

Another reason this shape was chosen for the base was because of its ease to model in

SolidWorks. The insert portion of the case was simply a combination of circular and tangent arc

extrusions and cuts on each side face of the rectangular base because they would be easy to

model onto the faces and fit the exact shape of hammer head inserts. The full case consisted of

two pieces, one with a 2 mm groove atop the face of its walls (created by extruding a 2 mm

thick rectangle around the interior base) and an 18.6 mm diameter extruded cut hole trough

the bottom interior rectangular face and the other with a 2 mm extrusion atop the face of its

walls. This was to allow ease of case assembly without the need to remove the handle from the

head first. The tongue and groove joint was selected as the locking mechanism because of its

ease of modeling and assembly in SolidWorks as well as practical, real-life examples of its use.

Most case features were dimensioned such that their dimensions were 0.2 mm greater than the

dimensions of the hammer head plus insert assembly. This was to provide a secure fit for the

hammer head while remaining relatively close to the “perfect/exact” measurements for the

head and to ensure that the case would work in situations where the hammer head’s

dimensions were off. A tolerance of − 0.1 mm was selected for all features of the case as this

would still allow all case feature dimensions to be greater than the hammer head dimensions,

which means the hammer head would still fit, only a little tighter.

Appendices

All engineering drawings of individual parts and assembly

Any other additional information that would help to improve the clarity of the

final report:

Hammer Case Render:

Full Hammer plus Case Assembly:

Full Hammer Assembly:

Role/contribution of each member in the term project:

Akash Oommen:

• Wrote the executive summary and the introduction

• Completed his individual 10 free-hand sketches

• Modeled the hammer head and handle

• Designed the case

• Made the full hammer assembly and the full hammer plus case assembly

• Completed the engineering drawings for the hammer components (head, handle and

inserts)

Ameer Rashid:

• Made the title page

• Completed his individual 10 free-hand sketches

• Modeled the hammer handle and both parts of the case

• Wrote the ideation processes/rationale for design selection and the first half of the

discussion for final design

• Edited/formatted the report

• Selected the colors/materials for the hammer components (head, handle and inserts)

• Prepared the final renders for the full hammer assembly, full hammer assembly plus

case and the case assembly

Garen Keleshian:

• Wrote the 2nd half of the discussion for final design and the conclusion

• Completed his individual 10 free-hand sketches

• Modeled the inserts

• Completed the engineering drawing for the hammer case