stainless steel fasteners

huangyhg

stainless steel fasteners
hi!
i am having a few problems being reported to me about the stainless steel fasteners used on a machine currently being built. the fasteners are of a4-70 grade and use nyloc nuts. when they are being tightened up by the fitters some of the fasteners are suffering from thread stripping (on the screw),some have sheared off completely. the ones that have tightened up ok generally shear off when trying to undo them! i specified a torque value given by the fastener supplier and the fitters are saying that the nylon patch in the nut is "jamming" up the threads on the nuts. i'm not sure as to wether the torque value is wrong or the fitters are right. has anyone experienced a similer problem with locking nuts? which are the best to use on stainless steel fasteners? ive contacted the supplier about this but they are busy and can't get an engineer over until next week and i need an answer sooner (management!)
the screws are m8x1.25-6g a4-70, nyloc style full nuts, 25nm torque value (for reusable fastener),washer under screw head and nut. hope someone can help!
thanks.
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womble...
we do not deal with these type ["graded"] fasteners in aerospace/acft engineering.
suggest you copy this topic to both of the following forums and see what happens:
hi, my apologies for posting in the wrong forum. did not know the others mentioned above were there!