magnetic permeability of fasteners around magnetic flux valve
magnetic permeability of fasteners around magnetic flux valve
(OP)
Does anyone know of a reliable guideline for selecting fasteners around a magnetic flux valve based on magnetic permeability? The original fasteners that attach an access cover were bronze per AN509 but these are no longer available. MS24694 CRES screws have a magnetic permeability of 2.0, but that exceeds the permeability of the original bronze screws.
This is for a Sperry C-14 Gyrosyn compass system. This is now part of the Honeywell empire and I haven't been able to locate a contact for OEM support.
This is for a Sperry C-14 Gyrosyn compass system. This is now part of the Honeywell empire and I haven't been able to locate a contact for OEM support.





RE: magnetic permeability of fasteners around magnetic flux valve
RE: magnetic permeability of fasteners around magnetic flux valve
MS20160 anchor nuts are stainless steel, and if you trace through the material spec's you can probably find an allowable permeability.
There are a number of anchor nuts, clip-nuts, and screws that are designed specifically for use in instrument panels, and accordingly they have magnetic permeability limitations in their material spec's.
Don't forget that equipment ground return wires (AND the metal structures they are attached to) carry electric current. Current = magentic field.
Flux gates are often found in aircraft wings. If this is the case for you, consider the proximity of your compass to control cables, rods, counter-balance weights, etc...
STF
RE: magnetic permeability of fasteners around magnetic flux valve
RE: magnetic permeability of fasteners around magnetic flux valve
Note how some mechanics may complete a wing inspection / all panels may be removed at the same time & fasteners grouped in a common container until reinstalled. A painted stainless screw will look identical to a steel screw.
RE: magnetic permeability of fasteners around magnetic flux valve