How do I check a drawing before it's released to the shop?
Have someone other than the author check it against a short written checklist: title block and revision, material and finish, every feature dimensioned and toleranced, and notes a shop can act on. The checker marks up a PDF, the author answers every mark, and the drawing counts as released only once it's in the released folder with a revision.
Why small teams skip the check
On a team of two to five engineers, the person who made the drawing is usually the only one who knows the part. Checking feels like a formality, so drawings go out after the author's own look, and the shop finds what was missed.
When there is a check, it often depends on one senior engineer. One small team told us every design review waits on their engineering manager, who ends up catching title-block errors, typos and missing dimensions instead of looking at how parts fit together. The quality of the check depends on who does it, because there's no checklist.
A checklist fixes both. Anyone on the team can do the first pass, and the senior engineer's time goes to the questions only they can answer.
Worked example: 160-0042 sensor bracket, first release
The bracket is a 1.5 mm aluminum sheet-metal part with two bends, a slot and four holes. The author has finished the drawing; another engineer checks it. The checklist lives in the team's shared folder and is the same for every part.
| # | Check | 160-0042 |
|---|---|---|
| 1 | Title block: part number, name, revision, material, finish, scale, units | Finish missing |
| 2 | Drawing matches the current model (measure a few features) | OK |
| 3 | Every feature located and sized | OK |
| 4 | Every dimension toleranced, directly or by the general tolerance block | Slot width had no tolerance |
| 5 | No duplicate or conflicting dimensions | OK |
| 6 | Datums make sense for how the part is held and mated | OK |
| 7 | Sheet metal: flat pattern, bend direction and bend radius shown | Bend direction not shown |
| 8 | Notes are specific and something a shop can act on | OK |
| 9 | Hardware and inserts called out with part numbers | OK |
| 10 | Revision block filled in for this release | OK |
Item 4 comes from the basics of dimensioning. The fundamental rules of ASME Y14.5, as summarized by eMachineShop, include that all dimensions must have a tolerance and that dimensions and tolerances must completely define the geometry and its allowable variation (eMachineShop).
Step 1: The author self-checks first. Run the same list before asking anyone. It's quicker for the author to catch the obvious misses.
Step 2: The checker marks up a PDF, not the native file. Export the drawing to PDF, mark each issue on the sheet, and number the marks. The checker doesn't fix anything; they only find.
Step 3: The author answers every mark. Fix it, or reply with why it stays. For 160-0042, the author added the finish note, toleranced the slot, and added the bend direction.
Step 4: The checker looks once more. Only at the marks, not the whole sheet again.
Step 5: Release. The drawing becomes Rev A only when it's in the released folder, with a matching STEP and the checker's initials in the title block:
/160-0042 Sensor bracket/
/released/
160-0042_RevA.pdf
160-0042_RevA.step
/check/
160-0042_RevA_check-marks.pdf
Export the PDF and STEP from the same revision; see The STEP and the drawing disagree: which does the shop build to?
Ways to check a drawing
| Method | Good for | Main risk |
|---|---|---|
| Author self-check | Catching obvious misses fast | You don't see what you didn't think of |
| Peer check with a written checklist | Small teams; consistent results | Only as good as the checklist |
| Senior engineer review | Fit, function and process questions | Becomes the bottleneck if it covers everything |
| Ask the shop | Manufacturability questions | Late; they'll quote what you send, as it is |
| Formal checker role | Larger teams releasing many drawings | Overhead a team of three can't carry |
Shop input is still worth asking for on features you're unsure of; see How do I ask a supplier for DFM feedback before release?
When this stops working
- The shop keeps finding the same kinds of issues.
- Drawings wait days for a checker.
- The checklist hasn't changed since it was written.
- Nobody can tell which version of a drawing was checked.
At that point the check needs to be tied to the revision itself, with the marks and answers kept alongside it, not in a separate folder.
FAQ
Who should check a drawing on a small team?
Anyone who didn't make it. A second engineer with a written checklist catches most misses, and the senior engineer can then focus on fit, function and process.
What should a drawing checklist include?
The title block and revision, material and finish, every feature located, sized and toleranced, no duplicate dimensions, sensible datums, and notes a shop can act on. Add the items your shops keep finding.
When is a drawing actually released?
When it has a revision, it has been checked, and it's in the place everyone gets drawings from. A PDF in an email is not a release.
Should the shop check my drawing for me?
Ask them about features you're unsure of, before release. Don't rely on them to find missing tolerances; many will quote and make what's on the sheet.
Internal links
- How do I run a design review when reviewers don't have CAD?
- How do I check that a drawing revision lists every change?
- The STEP and the drawing disagree: which does the shop build to?
Sources
- eMachineShop, GD&T fundamental rules (per ANSI/ASME Y14.5): https://emachineshop.com/gdt-rules
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