CAT excavator bucket size chart. The right bucket depends on more than width. Linkage family, stick pin diameter, link pin diameter, face spread, and pin spread all matter. If any of these are wrong, the bucket may not mount at all. A 312 machine uses 65 mm stick pins and a 221 mm face spread. A TB family machine uses 110 mm stick pins and a 441 mm face spread. Width matters, but it comes after fitment. Common widths for 312 machines run from 18 to 60 inches. TB family buckets range from 30 to 80 inches. Duty class also affects performance. General duty suits lighter soil. Severe duty handles rock and abrasive material. A cleanup bucket is wider but not meant for heavy digging. Check pin size and ear spacing before width.