How to request accurate CAD or samples for CZ brass designs?

Provide a fully dimensioned 3D model with named datums, wall thickness callouts, and section views at any critical junctions (stone seats, shanks, gallery). Include the intended manufacturing method (lost wax, die casting, or CNC) because minimum reliable thickness and radii change by method. Always send a solid model (not surface-only) and one marked drawing with critical tolerances and finish notes; that prevents ambiguity during tooling and casting.

Standard exchange formats are STEP (.step/.stp) and IGES (.iges/.igs) for solids and neutral CAD transfer; Parasolid (.x_t/.x_b) is also commonly supported. STL is acceptable only for rapid-prototype printing (it lacks native units and precise surfaces). Include a 2D PDF or 1:1 DWG/DXF with critical dimensions and a native CAD file when possible to speed revision cycles and avoid translation errors.

Specify plating chemistry (e.g., rhodium, vermeil-style gold plating), target thickness in microns, acceptable color/brightness standard (Pantone or sample reference), and any post-plating finishing (polish, matte, brush). Request measurement methods—XRF for composition and coulometric or cross-sectional micrometry for thickness—so supplier and buyer agree on acceptance criteria. Add clear exclusion zones where plating is not required (e.g., interior contact surfaces).

Use a staged approval workflow: 1) CAD review with explicit stone-seat callouts and 2D cross-sections, 2) resin/printed master to validate fit, 3) cast-and-plated sample with loose-set stones for fit testing, 4) fully-set sample for retention and finish verification, 5) documented inspection (photos, CMM or calibrated caliper readings, and setting-retention test). Require sign-off at each stage and record changes to prevent downstream setting issues and miscommunication.

Always specify stone diameter in millimeters with tolerance (e.g., 2.50 mm +0/-0.05 mm) and preferred calibrations or vendor SKU when using calibrated CZs. Provide seat diameter, seat depth, and intended setting type (flush, prong, bezel, pavé). If possible, ship a master stone or stone gauge to the supplier or request a stone vendor spec sheet; that eliminates errors from differing stone manufacturers and ensures consistent seat geometry.

Ask for a First Article Inspection package including: scaled photos (macro and detail), a dimension table referencing CAD datums, CMM or calibrated caliper readings for critical tolerances, plating thickness measurements and composition (XRF), and stone-seat measurements (diameter/depth) plus retention test results. These verifiable data reduce subjective approval and give objective pass/fail criteria before full production.