Hapstone S4 Knife Sharpener (Only on Kickstarter)

Hapstone S4 — Easy Sharp Every Time

A compact and universal sharpener that brings professional results to beginners and experts alike. Durable, intuitive, and ready to sharpen any knife with ease.

Sharp Knives Made Simple

A dull knife is no longer a problem. With Hapstone S4, anyone can restore a razor-sharp edge in minutes — no skills required.

We’re So Back

Seven years ago, Hapstone launched our first Kickstarter project — the Hapstone M2 sharpener. In 2018, 163 backers pledged $33,636 to bring it to life. Six years later, in 2024, we returned with Hapstone RS — and 566 backers pledged $164,634, making it our most successful campaign yet.

Now we’re back again with Hapstone S4 — our most compact and universal sharpener ever. Why Kickstarter? Because crowdfunding keeps Hapstone independent, customer-driven, and directly connected to the sharpening community. Your feedback has always been the spark behind our innovations, and Hapstone S4 is the next step in that journey.

Back this project today and get Hapstone S4 with an exclusive 30% Kickstarter discount.

What Hapstone S4 Does

A sharpener that fits in the palm of your hand — yet delivers the precision of systems that cost $400–$500. With smooth angle adjustment, secure knife clamping, and flip-over sharpening, Hapstone S4 makes your knives razor-sharp in minutes.

We’ve been designing sharpening systems since 2012, and with S4 we’ve put all that experience into one compact tool: simple, stable, and effective. Just set the knife, choose the stone, and enjoy sharp edges every time.

• Perfect for kitchen knives, EDC, outdoor, and hunting knives.
• Compact size with pro-level accuracy.
• Keep everything organized — add the Hapstone case to store your sharpener, stones, and accessories together (available at a Kickstarter discount).

 

This product cannot be purchased on this website.

You can support the Hapstone S4 project on Kickstarter by clicking the “Support the Project” button and become one of the first to receive the new sharpener.

Explore the campaign and support our project today.