1) The document describes a Creo computer aided design project to model an adjustable spanner. 2) The spanner consists of three main parts - the main spanner body, a movable jaw, and an adjustable screw. 3) Views and drawings of the completed CAD model are provided, including an engineering drawing of the movable jaw with dimensions.

1. 1
School of Mechanical and Materials Engineering
MEEN 20060
Mechanical Engineering Design 1
Creo Computer Aided Design Project
2014/2015
Student Name: Alan Murphy
Student Number: 13360891
Date: 25/3/15
Design Title: Adjustable Spanner

2. 2
Design Title: Adjustable Spanner
1. Introduction
The aim of this project was to design a mechanical part or system using CAD (computer
aided design) software. In this case, the software used was Creo Parametric, running on my own
laptop. The first part of this project was started on the 21st
of March and was completed by the 25th
.
I chose to model an adjustable spanner, as I believed that it was suitably challenging to
design using CAD software, while at the same time containing few enough parts to not be overly
time-consuming. An adjustable spanner is a hand-held tool that can be used to grip objects of
various sizes for the purposes of twisting or tightening, as the jaws can be moved further apart or
closer together as needed.
The spanner consisted of three distinct separate parts, and while each part was modelled
from scratch, each of the parts required knowledge and techniques learned from previous design
exercises to complete. For example, all of the parts required basic knowledge of extrusions and
referencing, while a helical sweep was required to
model the adjustment screw. The use of a pattern
and a datum plane also aided in the modelling of
the movable jaw.
See to the right for a picture of the actual
spanner that this project was based on. All
measurements were taken with a ruler, and as
such are not accurate representations of the
actual dimensions of the spanner.

3. 3
2. Major component parts
Main Spanner Body: The largest part in this project,
consisting of the grip and the head, as well as a hole for
hanging the tool when not in use. Rounded to provide a
more comfortable and ergonomic grip, as well as to
remove any potentially dangerous sharp corners or stress
concentrations.
Movable Jaw: This jaw sits into the keyway of the main
spanner, and its position in relation to the fixed jaw can
be adjusted as required using the adjustment screw
(below). The grooves along the bottom of the jaw fit
around the adjustment screw and allow the jaw to
move as the screw is turned.
Adjustable Screw: Fits into the main body of the
spanner and is secured with a screw (aside from the notch where the screwdriver would turn the
screw, the screw is not detailed). Screw thread fits into the grooves along the bottom of the
movable jaw. When the screw is turned the jaw moves with it, allowing for the distance between
the fixed and movable jaw to be altered as needed.

4. 4
3. View of completed model
Pictured below are multiple views of the final piece, including a view of the entire model, an
exploded view and a close-up of where the movable jaw and adjustment screw interact.

5. 5
4. Drawing, Dimensions, Tolerances
Pictured below is a complete orthographic view of the spanner, as well as a detailed
engineering drawing of the movable jaw with dimensions and geometric tolerances.

6. 6
5. Discussions and Conclusions
Overall, the model turned out very well. No major issues arose during the modelling of the
spanner, and any small mistakes made were rectified with reasonably little difficulty. All the parts
fitted together as desired in the final assembly; however the movable jaw needed to be adjusted
manually to prevent clipping with the screw.
The main files for this project are as follows:
 de4_spanner_body_finished.prt
 de4_movable_jaw_finished1.prt
 de4_adjustment_screw_finished.prt
 de4_assembly_finished.asm
 de4_drawing_finished.drw
 de4_movable_jaw_geotol_finished.drw
A small difficulty arose with the Creo software when modelling the movable jaw. It was
desired that both jaws of the spanner have the same profile, for aesthetic as well as functional
purposes (any stress in the spanner while in use would therefore be equally distributed across both
jaws). However, as Creo does not allow two sketches to be open at the same time, even on different
parts, it became inconvenient switching between the sketches of both the movable jaw and the
main spanner body to ensure that the profiles were identical. This was a minor issue and did not
majorly impact on the project as a whole.
Given more time, I believe the adjustment screw could be modelled with extra detail. On the
actual spanner, there is a textured finished on the adjustment screw for increased grip, thus making
it easier to turn. The screw is also attached to the main body of the spanner with a smaller screw.
Further time would have allowed for the modelling of these details and resulted in a higher-quality
end result.