This spring we ground a set of D2 tool steel wear plates for a stamping die application. The plates were hardened to 60–62 HRC before they came to us, and the customer needed both faces flat to within 0.0002″ with a surface finish of 16 Ra or better. That’s tight work, and it keeps us honest.
We ran these on our Brown & Sharpe surface grinder with an aluminum oxide wheel — a 46-grit for rough stock removal and a 120-grit for finishing. Magnetic chuck holding was solid; we just had to be careful with heat buildup. D2 is notorious for grinding cracks if you push too hard, so we took light passes at 0.0005″ depth and kept the coolant flowing continuously.
Final flatness checked out at under 0.0001″ across the length, well inside their callout. Surface finish measured 12 Ra — better than spec. The customer was pleased and said they’re replacing all their old wear plates over the next few months. We’ve got the next batch scheduled for June.