Knowledge

6 articles on choosing and specifying fasteners — the reasoning that a dimension table cannot carry.

Selection

2 articles
SelectionHow to choose a bolt property class8.8, 10.9 and 12.9 are not simply better versions of each other: what the numbers mean, when the upgrade makes a joint worse and how to match the nut.SelectionHow to read a fastener part numberA part number like DIN 912 M6x30-8.8-A2A carries five separate facts. How to break the string down and check a specification against what arrives.

Threads

2 articles
ThreadsThread pitch, coarse and fine — what actually changesCoarse and fine threads of the same diameter are not interchangeable, and the pitch number is not the only difference: strength, sealing and tapping change.ThreadsTap drill size and thread engagementGetting the tap drill right, and knowing how deep a thread must engage for the bolt to be the weak link rather than the thread.

Standards

1 article
StandardsDIN vs ISO: when equivalents are actually interchangeableDIN and ISO standards listed as equivalent do not mean the parts swap without checking: where the differences hide, and how to verify a substitution.

Materials

1 article
MaterialsA2 vs A4 stainless fasteners — why the strength number misleadsA2-70 and A4-70 look like high-strength grades but are weaker than a plain 8.8 bolt: what the stainless grades mean and how to choose between A2 and A4.

Reference data

All specificationsStandardsThreadsSizesMaterialsProperty classesComparisons