GENERAL Seat belts are designed to be fitted to (Pre-designated) Anchorage Points, fabricated by the vehicle manufacturer, to help position the webbing correctly and absorb loads in an accident. They are generally fitted using 7/16" UNF Set screws.
Most cars have anchorage points although they may be hidden behind trim. Where Anchorage Points are not available a level or restraint may be provided by fabricating suitable points. To assist the fabrication we can supply 50 x 42mm plates with 7/16" UNF nuts attached (Part Number 681/4), but we cannot advise to their location or strength.