ZUFEK
Transitions and minimum section
Dimension the reduced section and both transitions relative to the functional surfaces. Explain whether it provides clearance, a particular elastic behavior or an assembly feature. A smaller shank changes the load path; geometry alone cannot substantiate a fatigue or stress-reduction claim without the relevant design assessment.
Review the route before fixing the quotation
For reduced & variable shank screws, review Swiss-Type & CNC Turning, Cold Heading + Secondary Machining, CCD Vision & Dimensional Inspection 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 section change; functional intent; mechanical verification. 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
A reduced shank does not automatically prevent cracking. Supply load and fatigue requirements for design review. 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.