DEMO — fictional range. Local brief only, NOT SENT. No personal data is collected or transmitted.
REVISION
A drawing without a revision is a drawing without a history.
Most disputes in a machining programme are about which revision was made. A revision log is what makes a delivered part defensible years later.
- Revision letter
- Every change, however small, gets one
- What changed
- The feature, the value and the reason
- Who asked
- The change came from somewhere, and that is worth recording
- When it took effect
- Which batch was the first made to the new revision
- What it supersedes
- Which revision the new one replaces
- Where it is held
- The controlled copy, and who can issue the next one
| Rev | Change | Reason | First batch |
|---|---|---|---|
| A | Datum moved from the outer face to the bore | The assembly is built from the bore | Example · batch 2 |
| B | Keyway widened 6 to 8 mm | The mating key changed | Example · batch 4 |
| C | Heat treatment moved before finishing | Movement after hardening | Example · batch 5 |
Why a datum change is a revision like any other.
Because it changes what every other dimension means while leaving all the numbers on the drawing identical. It is the change most likely to go unrecorded and the one that causes the most confusion later.
The habit worth copying.
Recording which batch was the first made to the new revision. Without it, a batch sits between two revisions and nobody can say which drawing it was made to.