Review the drawing before you quote.

Why the 3D model is not enough

A STEP without PMI carries the geometry but not the requirements: fits, thread classes, geometric tolerances, local roughness, treatments or what the customer wants measured. Often the thread is not even modelled: only the tap drill hole is there.

What to check, point by point

1. Title block and notes. General tolerance standard, material, heat treatment, coating and required certificates.
2. ISO fits (H7, g6…). They mean reaming, boring or grinding, and checking with a plug gauge or CMM.
3. Threads. Type, class and usable depth.
4. Geometric tolerances. Position, perpendicularity, flatness or profile, and from which datums. They may require special fixturing or machining in a single setup.
5. Local roughness. A demanding Ra on a specific area usually adds a finishing pass and a profilometer check.
6. Special characteristics and inspection. 100% inspection, a first article report, PPAP or capability studies: metrology hours that belong in the quote.
7. Revision level. Quote against the correct drawing and model revision.

Measuring costs too

If the customer asks for a dimensional report, an FAI or a PPAP, building the characteristic list, programming the measurement and writing the report are real hours. If they are not in the price, you pay for them.

If you design: fewer tolerances, better price

Every tight tolerance the function does not need is paid for in machining and inspection. Dimension all the geometry, but leave the general tolerance wherever there is no real requirement.

Where a characteristic list helps

With every characteristic numbered, with nominal and limits, you see at a glance what the drawing requires before you price it, and the same list is then used to measure. GALGA PMI builds it from a model with PMI or from a PDF drawing. The terms are explained in the glossary.