Key takeaways
- Name the material and its condition on the drawing
- Give every size a tolerance, or add a general tolerance block
- Call out threads by their standard, not just a diameter
- State the quantity and the revision letter
- No print? Send the part, photos with a scale and the sizes you have
A shop can only price and make what it can see. The clearer the print, the closer the estimate is to the part you expect. This guide goes through the items a machinist looks for, in the order they usually matter, and what to send when you do not have a print at all.
What does a machinist read first?
Most machinists look for three things before anything else: what the part is made of, how big it is, and how many are wanted. These three decide how the work is set up and what material is ordered. A drawing that leaves one out starts the conversation with a question.
After that, the eye goes to the tight features: bearing seats, sealing faces, hole patterns that must line up with something. Mark those clearly, because they take most of the shop's attention.
The checklist
Use this as a last check before you send a print. Each row is something the shop would otherwise have to ask about.
| Item | What to include | Why it matters |
|---|---|---|
| Material | Type, grade and condition, such as annealed or as supplied | Decides cutters, setup and the stock that is ordered |
| Sizes | Every dimension, with units stated | A missing size becomes a phone call |
| Tolerances | A tolerance on each critical size, plus a general block for the rest | Tells the shop which features matter most |
| Datums | The surfaces other features are measured from | Keeps related features in the right relation |
| Threads | Standard, size, pitch and class, and depth | A diameter alone does not define a thread |
| Surface finish | Only where it matters, such as sealing and bearing surfaces | Finish drives extra operations |
| Quantity | How many now, and how many over the year | Changes how the job is set up |
| Revision | A revision letter or date on the print | Keeps quote and part on the same version |
| Notes | Edge breaks, coatings, markings and anything unusual | Prevents surprises at the end |
Tolerances: tight where it matters, general elsewhere
A tolerance is the amount a size may vary from the number on the print. Tight tolerances take more time and more checking, so put them on the features that need them and use a general block for the rest. Anyone reading the print can then see which surfaces do the work.
When fits and positions are specified, many prints follow the dimensioning standard ASME Y14.5. The glossary entries on tolerance and GD&T explain the terms. If you are not sure how tight a feature must be, say what it does and let the shop suggest a sensible figure.
Material, quantity and revision
Write the material as precisely as you know it, because grades differ in how they cut and in what they cost. If you want a particular condition, say so. If you are open to a substitute, say that too.
State the quantity in two parts: the first order and what you expect over a year. A part that will be reordered is worth a proper setup, and the shop can plan for that. Add the revision so the print in your file and the print in the shop are the same.
No print? Send these instead
The shop works from specifications, drawings or samples, so a missing drawing is not a dead end. The most useful substitute is the part itself, or a worn or broken original. The next choice is photos from several sides with a ruler in the frame, the sizes you can measure, and the machine it fits.
For help, read how to photograph and measure a broken part and what to do without a drawing. Then send the files through the quote request, or call (775) 359-5570, Monday to Friday, 7:00 am to 3:30 pm.
Sources
- ASME Y14.5-2018, Dimensioning and Tolerancing (2026-10-18)
- Protolabs help center: quoting and files (2026-10-18)
- Fictiv: preparing files (2026-10-18)
