As it turns out, to bring a new product to life requires some crazy effort. Who could have thought?
How I designed and manufactured a tool for irregular contours tracing?
WHY I DESIGNED A BETTER CONTOUR GAUGE?
Back in 2019 Spring I was helping my brother with some car bodywork on one of his cars. We were using fiberglass material to create the shape of the front left wing's arch.
The problem we bumped into was that we couldn't figure out what exact shape we should create. We couldn't use right wing as the example as it's the opposite side, so the shape is backwards.
Few days pass and online I noticed a tool called contour gauge. It was 12 cm wide with short 10 cm teeth plastic. I looked as a great solution for our project!👏
I purchased it online and after couple of days I received it. I was amazed how such simple tool improved the efficiency of our car bodywork!
I realized that this tool could be applied by carpenters to trace irregular curves (e.g. when laying tiles, flooring).
Though, I noticed that the tool I bought didn't serve as good as it could.
- The tool was too narrow and short. I couldn't trace the whole part at a time
- Teeth were thick. It wasn't precise
- Teeth didn't lock. I couldn't fix traced template
I always wanted to create some tangible product on my own, so I realized that I could take this as opportunity. And I did!
DESIGN CREATION
I wasn't related with design area. So, online I hired a product designer. He drew me different sketches according to my requirements. It took me ~1 month to think and describe the exact requirements that I wanted.
Time on the project: 1 month
Requirements for contour gauge improvements:
- has to have a lock for the teeth
- has to be wider with longer teeth
- has to have side-by-side connection with multiple tools
After 3-4 weeks I got the results:
Sketch #1

Sketch #2

Sketch #3

Sketch #4

I was leaning towards sketch #2. After some debate with the designer we aligned that this is the best version to go further.
Some extra costs later, I received the final design drawing with measurements.

I was quite happy with the initial results.
Next step was to bring the design to reality.
Time on the project: 2 months
PROTOTYPING Attempt #1
The designer shared with me specific files for creating 3D prototypes.
A local 3D printing company printed the me the product. This is the initial prototype #1:

Time on the project: 4 months
I never had any deals with 3D prints & didn't know what to expect. To be honest, when I received the product I was devastated.
My upgraded contour gauge was not functioning at all.
I realized that there's no chance I could create a well functioning tool without help.
PROTOTYPING Attempt #2
One day I was scrolling online and noticed an article. Some guy in Vilnius (Lithuania) creates various innovative physical products. He works with various startups and helps to bring useful daily product to life.
As I'm based in Vilnius as well, I approached him through LinkedIn.
Next week we met and I showed my crappy prototype. He was interested in my project.
Long story short - he took over the prototyping and after couple months created 3 prototype versions. Each was better than the previous one. It took several months do it.
Prototype #1

Prototype #2

Prototype #3

Time on the project: 9 months
I was so excited that my initial idea actually came to life and worked as I expected! After few attempts the lock for the teeth was functioning well, tools connected side by side perfectly. The size of the tool was how I wanted.
Upgraded tool's technicalities:
- 20 cm length
- 15 cm width
- 1 tooth 1.2mm thickness (130 teeth in assembled tool)
- Integrated lock to fix the teeth
- Side-by-side tools' connection system
The last part was only to manufacture my upgraded contour gauge version.
MANUFACTURING
Before I started with this project I had no idea how mass production for plastic products work.
Hot plastic is injected into a metal mold, cools off and the part of the tool comes out. This process is called mold injection manufacturing.
I started approaching manufacturers and immediately was hit into the wall when I showed the drawings of my tool.
The main issue: The tool was too complex for manufacturing.
My product designer created the tool for it to have as few parts as possible. Less is better, right?
Well, not in mold injection/manufacturing world. Fewer parts means complicated shapes. The manufacturer didn't agree to produce the tool which took me moths to design and prototype. 🤦
Long story short - the whole design had to be redone. My designer didn't know how mold injection works, so he wasn't sure how the design should be corrected.
I had to find another designer who had practice with mold injection processes and product design. After some time I found the perfect guy for that.
After several months he improved my contour gauge design, so that manufacturing could be smooth.
Time on the project: 15 months
This is the final prototype before manufacturing:

From the outside the tool looks like the previous versions.
But the inside everything is redone almost from basics.
The obvious change outside is that there are no screws anymore. It simplifies and improves assembly of the tool.
More kudos to my last product designer! This guy also aligned with mold injection maker about every detail and manufacturing itself. This part took most of the time and was the hardest. Injection molds had to be custom made with precision of less than 1 mm. Only with precisely made injection molds final product will function properly.
I had to buy injection molds. This is the only way to proceed with manufacturing and mass production.
It cost me a fortune, but I had no way back. I had to finish what I started.
After 4 testing rounds the final tool completed.
I've never been happier with this project😊 Hope you liked reading it!
Time on the project: 23 months
The project took me:
- Infinite sleepless nights 😴
- 7 prototyping iterations
- Infinite coffees with extra sugar ☕
- 2 years of my time
- majority of my savings💸
Never stop improving.
Karolis
P.S. Click below to see the final manufactured version of my contour gauge tool.👇
P.P.S. Currently I afford to manufacture only small amounts of the tool. The stock may not be always available.