Sharpening S390 Steel 🔥 The Rarest Production Knife Steel on the Kunwu Gringo 💀 @TSPROFSharpening

Today we’re sharpening the Kunwu Gringo in Böhler S390 Microclean — one of the hardest and rarest steels ever used in production knives. With a Rockwell hardness up to 67 HRC and extreme carbide content, this steel offers exceptional edge retention and polishability — but it’s also a true challenge to sharpen. We’ll be using the TSProf Alpha Stones and finish with a 0.5 micron TSProf leather strop, aiming for a perfectly mirrored edge and maximum sharpness. Along the way, you’ll see detailed microscope shots, a deep-dive into the steel's composition, and honest feedback on how the S390 behaves during sharpening. ✂️ Cut tests include paper, paper towel, and more 📏 Final BESS test score: You won’t believe the number 🔍 Full breakdown of sharpening angle, deburring, and stropping techniques 🔪 KnifeStock for the Best Knife Deals! 👉 https://link.knifestock.eu/yckrthwf My unpaid recommendation and personal opinion for TSprof products Shop ----- https://tsprof.eu #knifesharpening #tsprof