ICON A5 MM : General : Fasteners : General Hardware Specifications
General Hardware Specifications
100830-00
All bolts and screws shall have at least one thread protruding from the associated nut or nutplate, per AC43-13.1B Section 7-37.
Screw or bolt grip lengths shall extend completely through the load-bearing parts being assembled.
• To avoid nut threads engaging the unthreaded grip portion of the screw or bolt, varying combinations of washers, shall be used while maintaining the above minimum thread protrusion.
• Screw or bolt grip lengths may also be modified by one size from design to prevent nut threads from engaging the unthreaded grip portion of the screw or bolt and to allow for proper thread protrusion.
Flat Washers:
Flat washers may be installed under the bolt or screw head and/or nut as required to ensure appropriate thread engagement, avoid bottoming threads and allow for alignment of cotter pins in castle nuts. The maximum total washer combination is four washers. The maximum number of washers under the head or nut is two. If the minimum thread protrusion through the nut cannot be achieved due to variations in material thickness, a thin washer may be used. Likewise, if nut threads are engaging the unthreaded grip portion of the bolt or screw, a thick washer may be used. Thin washers may also be used in place of standard washers when castellated nuts cannot be aligned for safetying. A washer shall also be used if rotation of the bolt head would cause wear or damage to the underlying structure.
Locking Nuts:
Lock nuts may be reused limited times only. Lubrication must be used when reusing locknuts, see Approved Lubricants for acceptable lubricants.
Nutplates:
Riveted nutplates shall be installed with appropriate solid rivets. Fasteners inserted to nut plates must have proper lubrication per Approved Lubricants.
Threadlocker:
Threadlocker shall only be used if Nord-Lock washers are not specified. Threadlocker shall be installed per the manufacturer’s instructions for the particular threadlocker specified. Surfaces to have threadlocker applied shall be clean and free of grease, oil or contaminants. Surfaces shall be cleaned with isopropyl alcohol prior to threadlocker application.
Cable ties:
Cable ties shall be installed tight enough to adequately secure the locations of the items within the cable tie but not so tight as to crush those items. Cable tie tails, the unused portions of the cable ties protruding through the cable tie lock, are to be trimmed flush to .125 beyond the cable tie lock. Cable tie tails are to be trimmed at approximately 90 degrees to the cable tie to avoid creating sharps on the cut end.