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Fastener Knowledge Base

Not sure what a standard on your drawing means, or which type you need? Here we have put the spec notation, standard cross-references, materials and tolerances of common fasteners into comparison tables. Every page links directly to SFP's stock sizes in Taiwan — click a size to open the product page with price and stock status.

Product Guides

🔩 Screw selection helperFind screws by head type, material, size and length and add them straight to the cart; metric / inch thread pitch chart; calculate screw length from plate thickness and match washers and nuts; hex key size chart.Screw head & drive types (Chinese / English / Japanese)Photos and Chinese / English / Japanese names of socket head, hex head, button head, flat head, round head, pan head and set screws; Phillips / Torx / hex socket drives. Click a picture to see products with that head type.Dowel Pin Selection GuideISO 2338 / DIN 6325 standards, SUJ2 vs 304 material, and how to pick a tolerance type, with a list of stock diameters.E-Type Retaining RingsHow to read E1.2-and-up designations, DIN 6799 equivalence, and stock sizes in black oxide / stainless / nickel plated.C-Type Retaining RingsThe difference between external S-rings (DIN 471) and internal R-rings (DIN 472), which pliers to use, with stock sizes.Parallel and Round-End KeysThe wrong end shape won't fit: how to tell parallel, single-round-end, round-end and Woodruff keys apart, with stock sizes.Slotted and Coiled Spring PinsSlotted or coiled? Why the nominal diameter is the hole diameter, ISO 8752 / ISO 8750 standard cross-reference and stock.Washer Types ComparedSpreading load, locking or taking up clearance — which washer to use? Seven washer types and their standards, with stock.Choosing a NutHex, thin, nylon insert, flange and threaded inserts compared, how to read M thread-P pitch, and how to choose a locking method.Helical Thread Inserts and ToolsRepairing stripped threads and reinforcing soft materials: choosing 1D / 1.5D / 2D, the four installation steps and a full tool set in stock.Spring Lock Washer Size ChartNo. 1 / No. 2 / No. 3 size chart for M2-M39 and inch: ID, section width × thickness, max OD — tell the number by measuring thickness.

Standards, Tolerances & Materials

Material ComparisonHardness, heat treatment, corrosion resistance and typical uses of SUJ2 / S45C / SUS304 / 12L14 / SK7 in one table.Dowel Pin Tolerance SelectionMinus tolerance, h7 or plus tolerance (press fit)? Includes length tolerance conventions and a one-line rule of thumb.Equivalent Substitution TableCan't buy the specified standard? Which standards can substitute for each other and which need your confirmation first — a table confirmed by SFP engineering.ISO 2338 Standard GuideWhat ISO 2338 is and how it relates to DIN 7 / JIS B 1354 / DIN 6325, with stock diameters.🧮 Tolerance calculator & tablesEnter 8h7 to get the upper and lower deviations; enter 3(0/-0.014) to find the matching code and every tolerance code that meets the requirement. Includes shaft / hole tolerance tables and common fits.

Purchasing & Substitution

Overseas Part Number Purchasing GuideHow to buy overseas part numbers from your drawings in Taiwan: help checking local stock, or sourcing with a Taiwan invoice.Dowel Pins (English)Metric & inch dowel pins in stock in Taiwan, ISO 2338 / DIN 6325 equivalents — a one-page summary.

Find stock by standard

If your drawing calls out a standard, click it to see every stock size we have tagged with that standard. This section is generated automatically from the "standard" field of our product data — each new entry adds a new item.

Can't find the size you need? Email part numbers, drawings or a full BOM to sfp@sfp-tw.com or give us a call; our staff will help confirm the specification and let you know which items are available in Taiwan.

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