ZUFEKTheo Wan
Theo Wan is the editorial pen name used for ZUFEK’s practical guides on custom fastener specifications, manufacturing choices, inspection and procurement.
Focus of the articles
The guides help engineers and sourcing teams prepare clearer drawings and RFQs. Topics include shoulder and bore requirements, special drives, manufacturing routes, final material condition, surface treatment and acceptance planning.
Articles provide general technical and purchasing guidance. Application-specific design, safety requirements and manufacturing feasibility need review against the actual approved specification.
Articles by Theo Wan
Search all 42 articles ↗What to include in a custom screw RFQ
A useful quotation starts with a clear specification. A drawing is the best starting point, but a sample, sketch or assembly description can also help define the next questions.
Read technical guide →A practical guide to shoulder screw drawings
A shoulder screw drawing needs separate bore-fit, axial-stack, thread and final-surface requirements. Check both tolerance limits before sample approval.
Read technical guide →Five questions before specifying a captive screw
Specify a captive screw with its panel, retainer and mating thread. Review installation, released travel and tightened engagement as separate conditions.
Read technical guide →Choosing material for a custom metal screw
Material selection begins with the service environment and mechanical requirements. The best specification balances function, manufacturability, availability and verification.
Read technical guide →What affects the price of a non-standard screw?
A custom screw quotation reflects the complete specification and order conditions. Understanding the cost drivers can make a design review more productive.
Read technical guide →How to prepare an inspection plan for custom screws
Build an inspection plan one characteristic at a time. For each drawing requirement, record the acceptance condition, a suitable method, the inspection stage and coverage, and the evidence retained. The worked rows below show how to turn a shoulder-screw drawing into an inspection record.
Read technical guide →Cold heading or CNC turning: choosing a custom screw route
Choose the manufacturing route around geometry, quantity, material and required condition. A lower cycle cost does not always offset tooling or secondary work.
Read technical guide →High-strength screw coatings and hydrogen-risk review
A high-strength steel fastener needs a coating decision that considers both corrosion and hydrogen exposure throughout processing.
Read technical guide →304, 316 and 17-4PH: different heat-treatment questions
Stainless steel describes several material families. Specify the grade and final condition rather than writing one generic heat-treatment instruction.
Read technical guide →