ZUFEK
Treat the flange as a bearing interface
Flange diameter changes the contact footprint, while flange thickness and under-head geometry affect the way the part seats. Supply the mating surface and available clearance. A wide flange is not automatically a substitute for a washer in every joint; compare the actual bearing surface, assembly arrangement and drawing requirements.
Distinguish plain and serrated bearing faces
A serrated face intentionally interacts with the mating surface and may affect appearance or coating. A plain flange has a different contact requirement. Identify whether the surface is soft, painted or otherwise sensitive, and define any permitted marking. Avoid specifying a texture only by a product photograph when its geometry affects the application.
Check finishing allowance and thread engagement
Coating applies to a three-dimensional part, including the bearing face and thread. Review the ordered finish with the thread fit and seating requirements. Where the joint has a shallow tapped hole, compare usable engagement and the under-head stack so the screw does not bottom before clamping. Head diameter alone cannot establish that the joint will assemble correctly.
Link sample approval to the mating part
For an equipment cover, review flange clearance, head access, seating and the agreed visual condition on representative parts. Define flange diameter, thickness and any flatness requirement independently. Choose mechanical and coating checks according to the specification; a dimensional screen of the flange does not establish clamp load or corrosion performance.
Review the route before fixing the quotation
For custom flange screws, review Multi-Station Cold Heading, Cold Heading + Secondary Machining, Coatings & Surface Treatments against the drawing and quantity. Identify which features can be produced in the initial shape and which require a separate setup. A change to a functional shoulder, bore, drive or thread can change the proposed route as well as the inspection effort.
The drawing review should resolve flange dimensions; bearing face; thin or enlarged flange. Keep material condition and finishing allowance attached to those requirements. Define the acceptance condition for critical features and approve any proposed dimensional change before comparing samples with the original assembly.
From drawing to approved samples
Include the mating material and bearing-face requirements. A larger flange does not automatically prevent surface damage. Identify the drawing revision, prototype quantity and expected repeat demand. Where the first part is based on an existing sample, separately confirm material and hidden features rather than inferring them from appearance.
The typical sampling lead time, including tooling, is approximately 10–15 days. The schedule is confirmed after drawing review and agreement on the sample specification; material availability, special treatment and inspection requirements can affect the confirmed date. Confirm when the agreed schedule starts in the quotation. Sample approval and repeat-production delivery are separate milestones.