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Grimes landing light - what screw size
Posted: Sun Sep 20, 2020 10:46 pm
by meloosifah
Does anyone know what thread an MS5190-239 screw is? This is the designation for the 11 screws that hold the light in the wing. They are #6 machine screws but don’t seem to be 6-32. I’ve googled it to exhaustion.
Re: Grimes landing light - what screw size
Posted: Mon Sep 21, 2020 6:18 am
by 8342
The IPC that I have says that they are AN505-632-R10 screws.
Where did you come up with your number?
Rick
Re: Grimes landing light - what screw size
Posted: Mon Sep 21, 2020 8:13 am
by meloosifah
The Grimes maintenance document posted on this site under docs. I tried a 6-32 screw and it seems to be the correct diameter but the thread feels slightly off when threading it in. I could make it go but was worried about cross threading. Ironically, this seems to be the same thread that was used on the window side of the window latch on my plane. The original Grimes screws go right in but a 6-32 binds on the first full thread.
Re: Grimes landing light - what screw size
Posted: Mon Sep 21, 2020 12:48 pm
by 8102
As Rick stated the Cessna parts manual lists the screw as a AN505-632-R10, the AN505 spec is obsolete. The superseding part number is an MS35190-239 screw which should be a 6-32 UNC-2A thread. Are you using a hardware quality screw? If so it may not meet the tolerance requirements for the nutplate (or whatever) that's in the wing.
Gregg