I loved that Instructables was running a Contest about creating Tools. And this frankly nudged me out of procrastination to finish writing this up, as I think this has a nice twist on who we make tools for...
Although I have made many tools (some technically 'unique' - e.g. Rabbet Tool (LINK) - which helped me and a team of makers put a superman doll into space for under $500), one of the most memorable has been creating a tool for someone with a very unique need...
Kyle was born limited use of his left hand, after a complication while in utero. As long as he can remember, he's always wanted to be a hairdresser, and although he has made valiant efforts to create his own tools to hold hair (in tension to be cut), they all have fallen short of the ideal.
As part of BBC Two's Big Life Fix, I was tasked with trying to help Kyle realise his dream career. This Instructables is as much about how to approach a challenge such as this, as the final tool itself. I hope that it is a useful guide and an inspiration not to underestimate the determination and courage of people like Kyle, and the power of communities who are interested in designing things that make a difference to people's lives.
If you'd like to do something similar, check out universities, or sign-up at Remap.org.uk
Step 1: Design, Build, Test. // Repeat...
Although this picture showing the evolution of the design, is abridged - the process remains clear - it was very much about iterating after the initial breakthrough (see 'Eureka!').
However, a very broad range of ideas were considered, both in terms of the mechanism (should it be motorised?), and what the input should be (I experimented with MYO bands (electromyography) to see if I could take electrical signals from muscles elsewhere in the arm to act as the 'control signal to actuate the comb - but this seemed (in hindsight) over-complex, and I later realised not practicle for sterilisation, and furthermore - more prone to maintence issues).
The learning was that sometimes you need to walk into some unlikely/stupid/over-complex scenarios to fully understand and evaluate the suitability of this.
One interesting, and very personal aspect of this journey was that this tool needed not only to function, but to feel befitting of Kyle's trade - both his environment and to be convincing to clientele. So it was not enough to just make a contraption which might function but would look unconvincing in a Salon.
Safe to say, this Instructable does not describe all the myriad decisions both Kyle and I had to make, which will hopefully be useful to learn from should you do something similar / for someone else. Indeed, everything from 'tool vs hand' to 'robotic vs flesh' were complex and unfamiliar discussions to both of us, and require time to give each other space to make the right decision together.
Step 2: Previous Attempts: Kyle's Hairdressing Prosthetic
Kyle had previously used a sports wristband to hold a comb in place. He'd remove this band, and then attach the 'clip', which has a modified wrist-strap with a spring-loaded clip attached.
The problem was that Kyle had to apply a lot of force to actuate the clip, which was also not 'subtle' (precise enough) enough to grasp all the hair. [One can really appreciate how specialised the human hand and a craft such as hairdressing is in times like these!].
A final issue was not obvious as first, but made total sense in hindsight: The clip was attached to his wrist, not his hand/fingers. This meant that he was having to move his whole arm, when really his hand was all that really needed to move, to orientate for the task at hand.
Step 3: Gaining Perspective on Kyle and the Goal
As with so much in design - you have to dive in and be a part of the process! I had a crash-course in hairdressing from Yvonne, Kyle's wonderful tutor at Marvel Hairdressing Academy, Swindon.
As you can see from my frantically scribbled notes, there were some 'core' skills needed to get a basic haircut done: The hair needs to be parted, and then layered in a certain way to ensure the cut is even and stylish.
What also became clear was that Kyle couldn't simply use a fixed comb and electric clippers. As although the 'straight-cut' for most chaps is fine, most women's hair is defined by a quality 'feather-cut', which is all attributed to the skill of the use of the scissors.
This meant that Kyle had to only use his right hand for cutting with scissors, but his left hand needed to comb and hold in place to be cut. As shown in the picture, Kyle's fingers were not long enough to manage large enough quantities of hair, or flexible/dextrous enough to control it.
Even his current comb-modification only worked when the hair was 'down' - and he couldn't life it up, so was unable to do a significant portion of the styling needed for a good haircut.
A tool was essential...
Step 4: Learning From History
It was quite a humbling, and at times, moving experience - to see these artefacts on display at Strathclyde University's Biomedical Engineering Dept. which included Prosthetic and Orthotic specialities. One can see the labour of love and care that must have gone into these devices to help people who had few options in life.
One can only imagine the emotional journey one would have to go through to be at once liberated by a device, which no doubt was an improvement, but also may still have disappointing limitations.
The 'poundland hand' was included as a advisory note from the specialists - who stressed that although this was primitive and seemed laughable in a 'medical history cabinet'... as a cost-to-functionality ratio, it was very high performing - and students (most certainly including me!) were often encourage to 'keep it simple' wherever possible.
Looking back, it was fair to suppose that this was a key moment in my journey of working with Kyle, as it underscored the importance that although fancy tech is seductive, it add risk of breakdown and maintenance, and on one of the most effective prosthetics was the 'hook' - operated by a pull cord - as this was totally intuitive, and in tune with the body's natural approach to interacting with objects.
I realised that my task was not to replicate the extraordinary nuances and power of the human hand - but rather to create a tool which would work in harmony with Kyle's capabilities. I am indebted to Arjan Buis & Sarah Day for their counsel and open-mindeness to the whole 'design for telly' process.
Step 5: Eureka!
The moment of inspiration struck when using my electric hair 'clippers'!
I realised that the reciprocating motion of the twin blades, when low on battery used to snag my hair, which was uncomfortable as it pulled - but did not cut - my hair!
This painful memory, made me realise that if these twin blades were dull, and moved while hair as passing through, they would 'grip', rather than cut hair. Likewise, when moved again, the hair would flow through again - like a comb.
This tiny insight* allowed me to imagine what it might look like - when scaled up with two normal hair combs! I immediately went to a pound-store and tried to fix two combs together in such a way that they could be 'locked' and 'unlocked' while hair passed through their teeth...
*(Although a little 'TV' recreation shown here, this insight was the genuine inspiration!)
Step 6: Connecting Things Safely
Safe to say, I'm not a prosthetics expert - so I spoke to Arjan and Sarah again to 'sense check' the design. Fortunately, they felt the design was not just functionally sound, but also addressed some of their points about not being overly complex (risking breakdown) and also that it's simplicity might mean it is more likely to be acceptable for Kyle.
Arguably a longer discussion than afforded here on Instructbales, but we also discussed the emotional and ethical impact of this device on Kyle as a person. Sometimes these nuanced considerations are overlooked at the early stages of the design, when enthusiasm is high (or low!) and so it was a good time to have some calm reflection and constructive critique. It helped me move the design forward considerably, and with more conviction that this was not about 'fancy tech' but efficient design....after all, Scissors themselves are hard to beat for their simplicity!
As shown, Arjan drawing on his hand the best placement of the proposed 'socket'. I loved the down-to-earth nature of both specialists :o)
Step 7: Fibreglass Socket
Showing the end result first, this was a long process of starting with many discussions of how best to attach the comb to Kyle in a practical way.
Much of the exploration was taking Kyle from his previous prototypes (which were bound at the wrist) and re-thinking how to do this when able to move freely - from his hand. It sounds straightforward, but was a significant stage to get right with myriad options to select from.
Step 8: Version 2.0
This shows the early design of creating the 'dovetail' running system for the two combs to pass past each other (and un/lock the hair, as desired).
It was clear that the combs needed a convincing 'click' into place, and to apply the lock when Kyle was not moving the combs past one another with his other hand. This mechanism was initially borrowed from a toggle switch, and later evolved to precision spring loaded grub-screws.
Step 9: Click-Lock Test
As you can see, this video was not only testing the mechanism, but also the position of the comb on his prosthetic socket. I watched and re-watched this clip to study how best to combine these and allow easy exchange with other future tools...
Step 10: Casting - Freedom of Movement
These were casts taken in the Salon.
These preliminary casts (done in Alginate casting jelly) allowed Kyle to move his hands in 4 different poses, so I could understand the 'max' and 'min' ranges of movement.
A big issue was (as mentioned earlier) that Kyle was not able to actuate any fine control, or particularly forceful control, so this ultimately informed the need to allow his other hand to take the lead on this.
Many hours were spent inspecting at these and wondering how to gain an insight - enough for the ideas to come. They didn't make the edit on TV, but arguably were one of the most valuable things I did in the research phase (other than getting to know Kyle better, of course!).
Step 11: 3D Scan --> CAD Modelling
The Casts of the hand were scanned using a 3D Scanner at a Imperial College London. These are often available at Hackspaces and Makerspaces, and although quality is not mm precise - I needed a 'close enough' model to iterate on. Like clothes - the final fitting would catch any slight issues.
I evaluated the best place to position the tool, with the minimum of connection points, and complexity to change/repair if needed.
As shown in the final picture - much of the reality of 'Design' is jumping between CAD and a 3D print to test out an idea... It's not great TV, but is critical to refining the design. This stage probably had over 20 iterations to perfect the mechanism.
Step 12: Refining the Design
This was a great stage of the project - Kyle was now cutting hair, with the prototype working great!
It's hard to describe the feeling to have arrived at a 'click-lock-cut-unlock-comb' loop of work, that was so fast, that even without any practice, Kyle was stuck into the task!
Dare I say it, I think the producer was a little worried it all looked too easy, but the truth was that it was months of exploration that lead to a 'Eureka' moment. Often in design, I find that one has a 'gradually - then suddenly' progression with idea, but I think the 'gestational period' of thought can't be underestimated.
Step 13: Assembly: Fibreglass Meets 3D Printing
This was probably the most nerve-wracking part of the build. All other things can be re-build, or purchased again...but this was drilling into the only mould/cast we had created for Kyle in Fibreglass.
I also started to begin to develop the system for interchanging the tools easily, as although the comb was apparently 80%-90% of the job, the remaining other functions were also part of what make a great Salon experience complete, so those had to be developed in parallel consideration: from painting colouring creams to razor blades!!
TIP: Sugru was used to help create a perfect fit between the Fibreglass and the 3D Print. By adding cling film over the Fibreglass, and allow the Sugru (attached to the 3D Print) while still wet, to take mould, this then cured over night to be a firm rubber. This removed any tolerance errors in CAD / Fibreglass mould. If you are replicating this project, this can really help interface the 3D print and the Fibreglass interface.
Step 14: CAD Overview
Understandably, this CAD is specific to Kyle. However, if one were to take a fibreglass prosthetic, and adapt from this - then the fiels can be edited to suit. (See SLDPRT Files)
Step 15: Real World --> CAD
A quick tip on working with detailed and to-scale parts in CAD...
I created an approximation of comb (and also the Fibreglass part) by taking pictures - and using this to scale, so that I could approximate 'real-world' object, within the CAD model. I took tips from YouTube videos like this. It can be especially useful to take pictures from x, y and z axis, and attach to the said planes of the CAD datum.
I later machined (routered) out a profile of the comb, such that it could be inserted into the groove in the CAD part, as you can see later on, using a multitool and a guide, such as the one shown. You could attach the comb in other ways, but I felt this would be stronger than just a face-to-face joint.
Step 16: SLDPRT FIles
Parts created in Solid Works.
These can be edited to suit your needs, and coudl be applied to a variety of prosthetic attachments.
Step 17: STL Files & Printing
STL Files, for quickness.
TIP: I would suggest printing in the shown orientation, to give strength and minimise warpage. The Runners can bow a little, but it is best to have the face which attaches to the combs finish last as this will be most straight. Likewise, the other face can be sanded down lightly to be more parallel.
Step 18: Multi-Tool Socket
As shown earlier, this too can connect with a variety of tools - all created around 4x4mm square stainless steel section bar. This was found to be an optimum balance of rigidity and weight.
The hole in the side need to receive a brass insert, and can be placed either by press, parallel pliers, or nestled-in with a soldering iron. I did the latter, as it is a stronger hold. I then added a dap of super-clue to 'wick' into an gaps to give strength.
Step 19: Runners & Steel
Similar to the tool socket, a Brass Insert is recommended here. Taking care not to protrude too far so as to obstruct the steel from running inside.
The channel in the other runner is to contain the steel. 4x4mm square stainless (LINK). This can be fixed with super glue, or epoxy. The latter is preferable.
Step 20: Adjustable Stop
This small red piece of plastic is a subtle adjutment piece: It allos you to tune the distance needed to 'lock' the hair. This is not to say that hair varies so much in thickness that you'd need to change it between cuts!
Rather, what I realised from using the tool, and observing Kyle, was that with confidence, one needs a less tight grip (i.e. smaller travel distance - and hence longer red piece) as one gest more experiences, and hesitates less. Hence suggesting printing a few off at once for the future.
I like that this piece is nicely hidden away inside, but can be accesses by unscreweing the clamping nut, and then sliding the two runners appart.
Step 21: Filament Choices
I actually dabbled with some fibreglass-infused ABS filament, but in all honesty, the weight difference was not much different to the normal ABS, but it may have improved in terms of less warpage now(?). Always worth trying different filaments to see which works best.
The benefit of ABS was that it could cope with hot water of cleaning, where as PLA would likely degrade much faster. ABS also can be washed with acetone nicely to get a smoother (and stronger) finish.
Step 22: Special Parts List
Safe to say a lot of this build is very tailored, and although I think the Instructables community appreciates this will be a case-by-case projects, some useful tools and tips include:
Spring Loaded Grub Screws. (LINK). & Brass Inserts (LINK).
These were invaluable to not only make the 'click-lock' mechanism small and compact, but because the pressure of the ball can be adjusted via the screw, the force Kyle had to apply to get the combs to trigger/slip past each other, was adjustable. Brass inserts were also used to connect the socket to the fibreglass piece (see next image).
Thread Locker (videly available).
Useful to add some friction to the Grub Screws to hold in place once the desired force was found.
Thumb Screws (from computer cases).
This is where the personalisation comes in - one can find a range of thumb screws in various styles and colours. Simply cut to size with a multitool.
Step 23: Assembly: Comb Mechanism
The Comb Attachment fits on top of the Fibreglass Socket, as shown.
This allows the 'trigger' or 'click-lock' mechanism to dock. As you can see there are multiple Brass Inserts, as I was finding out where was the best place to clamp the tools/combs/etc, and how much force was needed. (In the end, only one was needed - see images as show later)
The combs were routed to fit the 3D printed parts, and glued in with Epoxy. They were then sanded back to be flush with one another.
Lastly, other tools were checked for fit and utility.
Step 24: The "Swiss Army Knife" of Hairdressing Prosthetics
Although the crux of the project rested on the ability to cut hair, the final success of the project was the ability to interchange between tools safely, quickly and easily, so that the entire solution also enabled styling of hair too.
For Kyle and myself, these accessories needed to be 'centre stage' and look the part on the desk of a Salon, in front of the mirror. So the stand was a nice touch, to organise them for Kyle's easy access - but it also became a talking point for clients. Much of this project was about the little touches.
The last tool was a good example, which needed to evolve to be dual purpose - for brush and styling pic. The brushes once old can be removed and disposed of.
Step 25: Personalisation of the Tool
This was great fun being tutored by Master Jeweller, Mark Bloomfield, from Electrobloom. I learned loads about the process of jewellery making - both the design, craft and aesthetics of this. His input was invaluable in helping me deliver an aesthetic that Kyle would be proud to own. It was even a nice touch that he suggest we used Silver - not only because it was precious, but because it tarnished, it needed polishing - which in itself was a 'bonding' moment for Kyle, similar to that of say a motorcycle enthusiast, or saxophonist - taking that care to polish and observe the details in caring for a beloved item. His eye for organic designs is clearly inspirational when seeing the blue 'trigger handle', which is not only functional - but gives character to the tool.
This allowed the utility of the tool to be taken to the next level, such that it would be a credible looking thing for a client to see. Many of the techniques are similar to those used in Instructables Jewellery Class, so I will not detail them here.
Step 26: Put It to the Test
And I got a free haircut from Kyle =D
Watch the show online at BBC, or Youtube (ssshhhh!) (LINK)
Step 27: Kyle at Work
Kyle is continuing his training course, and is much more able to manage the various complex tasks of the profession, from the click-lock comb, and the various accessories.
Step 28: Gallery
Some pics of the final work.
Step 29: Kyle in Action!
Using the tool =)
Step 30: Thanks!
Thanks again for all involved in making the BBC Big Life Fix series 2. It was an incredible ride, and I hope the show's many other inventions are an inspiration to the Instructables community and beyond...
I hope this Instructable is a useful guide, and although has a lot of the back-story, is also helpful not only in iterating (or Remixing?) on this project, but also gives confidence to approach a complex design challenge such as this. Any questions, please do comment, or email me.
Second Prize in the
Build a Tool Contest