Bolt size for Seat belt Anchorages

[mazeroth]

SECTION 2.9 (3)(d) in STANDARD 185-00(01)states that the fastener is either a fixed nut or threaded section of material equal or greater than 12mm metric. The minimum full threaded depth is 9.5mm. I am going to use a plate 100mm x 50mm x 10mm thick with threaded holes for 12mm. My question is, does the bolt need to be a coarse or fine thread? For 10mm depth, a coarse thread 12 x 1.75mm has 5.71 threads, a fine thread 12 x 1.5mm has 6.66 threads, 16% more holding capacity!!!

[Justin]

Hi there

The standard says that the fastener must be be manufactured specifically for that purpose. Industry standard is for fine thread fasteners, so that's what should be used.