Show the cross-section and the finished part
A mullion is usually a vertical framing member. A transom is a horizontal one. Start with the extrusion section and the finished part drawing so the machinist can see how an end cut, hole pattern, notch or drainage slot sits on the installed profile.
Mark the inside and outside faces and the reference end. Define the datums for hole and slot locations and identify mirrored parts explicitly. A shared length and section can still produce two different parts if the features are handed.
Call out drainage and mating features
Drainage details vary by system. On the released drawing, show which face and chamber each weep or drainage slot opens into, its location and size, and any nearby gasket or sealant surfaces to preserve. Send uncertain geometry back to the system designer for approval before machining.
- End features. Dimension the mitre, cope or notch from the specified reference end. Identify the mating part or interface where it helps explain fit.
- Fastener features. Show hole size, position, depth and thread callouts where applicable. Identify blind and through holes and any countersink or counterbore.
- Surface protection. Identify exposed faces and any areas where clamping marks, chips or burrs could interfere with glazing, sealing or assembly.
Agree what the first piece must show
Ask the OEM quality or engineering lead to identify the features that need recorded measurements and any fit check or approval sample. Confirm the report format, who signs off and which work can proceed after sign-off.
Dimensional and fit checks verify the machined part against the release. Air, water and structural performance are evaluated under the system’s applicable test plan.