The heading explicitly excludes frameworks, so a grinding wheel sold with a permanently attached mounting arbor or flange assembly may shift classification depending on whether the mounting constitutes a 'framework' in the tariff sense. If the wheel is the principal element and the hardware is merely incidental, classification here may still apply; however, a CBP binding ruling is advisable for integrated tool assemblies.

Subheading 680421 covers wheels and similar articles where the abrasive is agglomerated diamond — synthetic or natural diamond particles bonded into a wheel form. Subheading 680422 covers wheels bonded from other agglomerated abrasives (such as aluminum oxide or silicon carbide) or from ceramics. The abrasive grain type, not the bond material, is the primary classification criterion.