How to choose the right drill point for a self-drilling screw
Drill point #1 to #5 explained: which point drills which steel thickness, how to read a DIN 7504 size, and the mistakes that snap screws on site.
Screw buying and technical guides
Practical articles for buyers and specifiers: drill points, coatings, standards, installation and importing from China.
Bi-metal vs stainless vs carbon steel roofing screws
A practical comparison of carbon steel, solid stainless and bi-metal self-drilling screws: corrosion, drilling capacity, cost and where each one belongs.
Screw coatings and salt spray hours explained
Zinc, yellow zinc, zinc flake, ceramic and Dacromet coatings compared, with what salt spray hours really tell you about outdoor life.
DIN 7504 vs ISO 15480: self-drilling screw standards
How DIN 7504 K, M, N, O and P forms map to ISO 15480–15483, and what to write on a purchase order so you get the screw you expect.
Coarse vs fine thread drywall screws
When to use coarse thread, fine thread or drill point drywall screws, which length to buy, and why phosphate screws belong indoors.
How to import screws from a China factory: a buyer’s checklist
MOQ, samples, specifications, inspections, packing, HS code 7318 and Incoterms: a step-by-step checklist for importing screws from China.
Concrete screw installation: hole size, depth and edge distance
How to install concrete and masonry screws correctly: drill bit size, embedment depth, edge distance, cleaning the hole and torque.
EPDM washers on roofing screws: sizes, bonding and installation
Why EPDM is used for roofing screw washers, how to choose 14, 16 or 19 mm washers, and how to tell a correctly driven screw from an over-driven one.
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