Engineering Knowledge Base
Precision Ball Metallurgy, ISO 3290 Standards & Application Guides
In-depth technical resources authored by DSP's metallurgy and quality assurance engineers for bearing, valve, automotive, and industrial buyers.
Consult Our EngineersComing Soon
Replace with page photo later
★ Featured Engineering GuideQuality & Metrology2 min read · 306 words
ISO 3290 & DIN 5401 Precision Ball Grades Explained: Sphericity, Ra & Lot Variation
How to read ISO 3290, DIN 5401, and AFBMA precision ball grade tables — understanding Vdws (ball diameter variation), tdw (sphericity), Ra surface roughness, and lot sorting.
By DSP Metallurgy & Quality Engineering Team · Updated 17 Oct 2026
Read Full Technical Guide →