: The 0.2mm depth is designed for "exclusive" fitment. It ensures that when you slide a bearing or a gear onto a shaft, it sits perfectly flush against the shoulder. Without that tiny 0.2mm of breathing room, the tiny leftover "fillet" from the machining tool would prevent a perfect 90-degree fit, leading to vibration and eventual machine failure.
To understand the value of , you first need to break down the nomenclature. The standard follows the German Institute for Standardization (DIN) 50900 series, specifically addressing electroplated coatings on metallic materials. din 509e06x02 exclusive
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