Machining & Assembly / Purchasing guide
A fastener hole should be specified as part of its hardware interface. Identify the fastener, washer, insert or mating feature that the design uses, then define the required hole geometry. A generic request for a countersunk hole leaves important details unresolved and should not be treated as a production-ready instruction.
Catalogue reference image. Confirm the quoted configuration against the agreed drawing.
Show the complete stack
Provide a section through the assembled joint where useful. Identify the composite component, mating component and hardware. State which face is visible and whether the fastener must sit flush. Avoid selecting a countersink solely because it looks cleaner; the joint configuration needs review against the actual design.
Dimension the feature
Define the hole type, location and required details on the drawing. If the feature changes from one face to the other, show that explicitly. Ask the supplier to review the geometry for the selected part construction and record any limitations rather than assuming all laminate thicknesses accept the same detail.
Agree the fit and inspection check
Specify whether acceptance is based on measured geometry, the intended hardware or another agreed method. Use the correct hardware revision during sample review. If the fastener changes later, reopen the interface check instead of assuming that the earlier approval automatically carries over.
Information to include in your enquiry
| Review item | Information to provide |
|---|---|
| Hardware | Identified fastener, washer or insert |
| Section | Assembly stack and visible face |
| Geometry | Hole type, location and detailed profile |
| Verification | Inspection method and reference hardware |
Frequently asked questions
Is “countersunk for a standard screw” sufficient?
No. Identify the hardware and the required geometry.
Can a visual flush fit prove the joint is suitable?
It demonstrates one aspect of fit. The design still needs its applicable engineering and acceptance checks.
Discuss your carbon fiber component
Send your drawing revision, intended application, quantity and acceptance requirements to Litian Yunde for a project review.