I was definitely drawn to the natural, curved designs, but I did experiment a little with super-ergonomic designs such as knives with aggressive thumb-ramps and finger grooves on the handle. While these over-stylised knives would probably be quite comfortable, I decided that they were far too aggressive looking for a supposedly ‘UK friendly’ knife. I wanted the knife to look more like a handy tool than a pointy weapon.

These were my favourite designs that I decided to develop further. They all feature a non-sharpened portion of the blade called a 'choil', which will help prevent the blade from closing accidentally, provided the knife is held firmly with a finger in the choil.

I liked these designs and wanted to develop them, but I found that drawing similar designs over and over on paper was not getting me any closer to a final design. Instead, I tried something new and edited the drawings in photoshop, altering their proportions until I had something that was an improvement, ergonomically and visually. This was a new technique to me, but worked very well. It was fun to digitally add a splash of colour to the drawings too.

I really liked developing concepts in this manner, so I drew some fresh designs with more details included and worked on those in Photoshop. Both of these designs ticked a lot of boxes, but the bottom knife lacked the organic flow of the previous concepts. The top design was very close to what I was envisaging, especially in regard to the lines of the blade and curved handle. I started experimenting with adding a pocket clip too.

With a fairly good idea of what the knife would look like, I began to work out how the lengths of the handle and blade relate to each other, and how I could achieve an optimum ratio that provides a good hand-filling grip and a sub-3” blade in an efficient design that makes the best use of these dimensions. To do this, I drew a more developed sketch of the knife design in 1:1 scale, and cut out a number of different length blades from paper. This allowed me to compare the different blade lengths to see what would suit the knife design. I determined that the optimum cutting edge was around 60mmm, with a large finger choil to keep the user safe.

Next I researched different methods of holding (but not locking) the blade open when in use. Although there are some unique and innovative ways of doing this, the vast majority of non-locking knives on the market use either a backspring or detent system. The backspring system is how traditional ‘slipjoint’ knives operate – a backspring is sandwiched between the knife frame and tensioned above the blade using pins/screws, putting substantial pressure on the blade tang. This gives it resistance when opening and closing, which can be very significant if the spring is strong.

Although the backspring slipjoint method is the most commonly seen in traditional knives, it has some downsides. Firstly, it requires tight tolerances to obtain a smooth action with a good snap on opening and closing; the best slipjoints are hand-fitted and finished by artisans, making high-quality examples very expensive. In addition to this, the high spring tension means that disassembly of these knives range from difficult to impossible – many are pinned closed to prevent it entirely. Because of this, a new system has come to prominence in recent years that uses a detent ball system. The general principle is that a ball bearing is pressed against a detent hole in the blade, under spring tension. When the blade is pivoted, the ball is forced out of the hole which provides some resistance depending on spring tension. There is a detent hole for the ball to snap into at open and closed positions. This is a cheaper, more mass-production-friendly method which is less reliant on precise hand fitting than a backspring. The fact that the detent system tends to give lighter resistance also means that these knives can also be more fidget-friendly, and can often be deployed quickly with one hand. For these reasons, I decided that a detent system would be the most suitable for my pocketknife.

With a basic design and rough dimensions in mind, I started the modelling process on Fusion 360. It might seem like a bit of a jump to go straight to 3D modelling, but as a CAD student it is through making models that I develop my ideas. Doing this allows me to test ideas and alter my designs easily without consequence, and the simulation suite in Fusion allows testing of the parts before the design is finalised. I started by forming the blade, but soon got carried away and designed the entire pocketknife - this was not wise, as I later found out.

While I really liked the look of this design, and I established a workable mechanism for the detent-ball opening system, there were some significant issues with this model. Through all my experimentation to find the best way of shaping a blade correctly (ensuring it had a thin, slicey edge) I neglected to check that it was a suitable length for UK carry until the end of the process. Even though it had started just on the limit, after various modifications and redesigns the cutting edge ended up about 4mm too long. In addition to this, the handle was proportioned in such a way that when the blade was closed there was a lot of empty space left, which is not an efficient design. The design did therefore not meet the brief. While I could have gone back and shortened the blade, this would only have made the wasted handle space worse – a complete redesign was required.

Despite these issues, I presented this design to the cohort since it was simply where I was at with the project by that point. It was well-received, and 3D lecturer Rob suggested that I used the wasted space inside the handle to add another tool into the design. While I had already decided to make a new, more efficient design with no wasted space, I did like the idea of including another tool. Knives with multiple functions (like multi-tools) seem more socially acceptable. First though, I needed to sort out the blade to handle ratio, so I started fresh on a new model, with the blade length being a critical dimension from step one. I found that by duplicating the blade and making it transparent, I could view it in the open and closed positions at the same time – this allowed me to set the blade length and design a suitable handle without constantly having to move the blade open and closed manually.

Now that I’d worked out how to create an efficient blade/handle ratio, I started thinking about integrating some other tools into the design. I think it’s always handy to have a cap lifter (bottle opener) integrated into a tool, and indeed some of my most-used knives feature geometry that facilitates this, as seen below.

I traced the shape of the bottle opener from the top knife (photographed above), as I knew that it worked well, and it was a fairly simple shape cut into the steel with no extra components required. Once I had established the geometry of the bottle opener and integrated the shape into the end of the knife handle, I worked on designing a lanyard hole (some people like to tie fabric or leather lanyards to knives to help remove them from a pocket etc.). I came up with a range of options to see which one best matched the flow of the design.

I felt the bottom design best matched the flow of the knife, and offered the largest diameter hole for ease of attaching a thicker lanyard made of thicker material (paracord etc.). The design as coming along nicely, but it still felt like there was some wasted space in the handle.

I therefore decided to try and integrate another tool into the design. There was very limited space available, but just enough for some tiny tweezers – Swiss Army Knives often come with these. I designed the end of the tweezers to fit snugly into the open cap-lifter area, making efficient use of all the space available.

This addition did, however, have some problems. Firstly, the placement of the tweezers meant that a rear-mounted pocket clip would have very limited mounting points, as typically the screws used to secure the clip go though to the backspacer and also act to hold the knife together. The tweezers would also be absolutely tiny – it can be hard to judge proportions on screen, but the knife itself is very small, so for the tweezers to fit inside they would need to be less than 4cm long, not practical at all. Due to these factors I decided to drop this idea – it would have added a lot of complexity and cost to the manufacturing process too.

I was ready to finalise the design, but came across yet another example of how I can sometimes rush forward with the model without fully inspecting that the base design principles work properly. Upon moving the blade into the closed position, I found that the stop pin – which defines the degree of pivot the blade can swing – was positioned in a way that wouldn’t let the blade open. This was a silly mistake that shows the importance of sorting out the basics before getting too carried away with extra features - this project taught me a lot about how to best approach a geometry-dependent design like this.

After working out a new position for the stop pin, I arrived at my final design. This long development process resulted in a pocketknife that was mechanically sound, UK-legal, and designed with as few components as possible with mass-production in mind.

I produced several renders in Fusion 360 which showed two possible colour configurations: A black-coated blade with purple G10 handle scales, and a satin-finished blade with natural micarta handles. Click to open full size.

The final stage of the project was to produce technical drawings using AutoCAD 2D. This turned out to be quite challenging since I had barely used the software since first year, and therefore had to refamiliarise myself with the shortcuts and operating procedures which differ massively from Fusion. I think it was valuable to do this because AutoCAD is a very commonly-used software in the engineering industry – it was definitely worth getting back up to date with it since it was likely I would be using it again after university. I produced dimensioned drawings of the key components, plus two exploded diagrams showing the parts and assembly. Click to open full size. Drawings are 1:1 scale unless otherwise specified.

To conclude the project, the models and drawings were uploaded to a Google Drive folder to act as a handover document, although a better term would be technical package. Click here to view it - note that the models are in STEP format for CNC machine compatibility. The goal of this project was to develop my modelling and drawing skills to prepare for industry, and I feel this goal was met. I made a number of mistakes during the process, mostly due to jumping too far ahead with the modelling before solid design foundations were set, but I learnt from these errors and have a much better idea of how I would conduct a personal project in the future. Time management was also an issue since I was juggling two NLT projects at once, but my time planner which featured all my modules was very helpful in organising my time and keeping me on track for submissions. I had mentioned the need for such a planner in previous years, so I am glad that I finally put it to practice. Overall, I was very satisfied with the end result, successfully meeting the brief criteria and producing an attractive and useful tool that I would love to be able to turn into a physical prototype one day.

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Sustainable Development Goal 10

Each of our modules has an associated UN Sustainability Development Goal that is designed to remind us that as designers, we should consider a range of sustainability principles in our work, ranging from climate change awareness to the promotion of peace and justice. Some of these goals tie in closely with the projects we undertake, but some do not, which can make them a challenge to integrate. For this module (Negotiated Design Final Project), the associated goal is Number 10 - Reduce inequality within and among countries. Inequality is a very broad term, which encompasses discrimination/social inequality, financial inequality, and inequality of opportunities to name just a few. There are a number of ways that a designer can take equality into consideration when creating something, especially those which can be improved through innovative and responsible design such as health inequality. An example could be socially-inclusive, environmentally-conscious architecture. Unfortunately I could not find a way of coherently linking my personal project to a particular inequality, but this is something that I now have a better understanding of, and will endeavour to consider how equality can be promoted when designing in the future.