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$550/Month From Four Little Rubber Buttons

  • Kevin Hardin

  • 3D Printing Engineer
  • $550 monthly revenue

📝 Kevin Hardin’s parents had an ebike that wouldn’t switch on. The rubber buttons on its control panel had rotted to goo in the sun, and one was the power button.

That panel was made by Currie Technologies, who went out of business several years back.

So: a $2,000 bike bricked by four bits of perished rubber, and no part in stock.

Kevin’s a 3D printing engineer, so he designed a replacement

I spent maybe 40 hours of design and engineering and made about 50 prototypes to get it right.

🤑 He sells the kit for $55, around 10 a month. That’s $550/month on $2 of materials and 8 minutes of work.

On why he can charge 27 times his material cost…

I am literally the only person in the world that solves this one problem.

👀 His entire marketing: two replies on old forum threads where stranded owners were searching, plus this 7-minute video with 212 views…

I get a few emails a week with someone asking, “Can you give me the link to pay?”

Pick a product forum, search for the discontinued part, and find the thread full of me-toos with no answer.

Then find someone who can print it – Kevin’s offering to design parts for a 50/50 split 🔥

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Updated: September 6, 2026

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