Grinding wheel grade notation — which letters indicate a soft grade? In grinding wheel specifications (e.g., A 46 K 8 V), the grade letter denotes bond holding power. Which letter range corresponds to soft-grade wheels?

Introduction / Context:
The ‘‘grade’’ in a grinding wheel specification represents the bond’s ability to retain abrasive grains. A ‘‘soft’’ grade releases dulled grains readily for self-sharpening, while a ‘‘hard’’ grade holds them longer. Understanding the letter ranges is crucial for selecting a wheel that balances wheel wear, cutting efficiency, and surface finish.

Given Data / Assumptions:

• Standard alphabetical grade coding is used.
• Soft, medium, and hard are relative categories across A–Z.
• Operation and work material influence grade selection.

Concept / Approach:
Conventional practice classifies grades roughly as: soft A–H, medium I–P, and hard Q–Z. Softer grades are chosen for hard or tough work materials to avoid glazing, while harder grades suit softer or gummy materials to avoid rapid wheel breakdown.

Step-by-Step Solution:
Map letter ranges to qualitative grade levels.Recall: soft = A–H, medium = I–P, hard = Q–Z.Select the option that matches the soft range.

Verification / Alternative check:
Wheel catalogs from major manufacturers present tables where the grade letter increases from soft to hard; A–H are consistently designated as soft grades.

Why Other Options Are Wrong:
I–P and Q–Z correspond to medium and hard ranges, not soft. A–P spans both soft and medium and lacks precision.

Common Pitfalls:
Confusing abrasive hardness (e.g., Al2O3 vs SiC) with wheel grade; they are different attributes.

Final Answer:
A to H