Revision schemes are important. For job shops where they rarely build the same part twice, it is best to keep the revision scheme simple as easy to understand.
For most metal fabrication shops that typically operate as a 'job shop' and infrequently release revisions, the following scheme is recommended:
Production Revisions: A, B, C
Initial Production Revision: -
Prototype Revisions: 1, 2, 3
Initial Prototype Revisions: 0
Add a Revision History Block to drawings after initial revision including:
Add a revision symbol to identify an item or area of change on the drawing
Multi-sheet drawings shall be maintained such that all sheets reflect the drawing revision level (KSC-GP-435, pg. 9)
ASME Y14.35 - Revision of Engineering Drawings and Associated Documents
MIL-STD-100G - Department of Defense Standard Practice for Engineering Drawings
KSC-GP-435 - Engineering Drawing Practices, Volume I of II, Aerospace and Ground Support Equipment
