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Snorkel to FM-150

JDA_BTR

Well Known Member
What is the torque for the hex 1/4-20x3/4 bolts that fasten the snorkel to the FM-150? Is there a value, snug, or ????

Also the washer in the plans is called out as a nas1149fo332p which I think is for an an3 or #10 size. I found some 1/4 washers in the bags and used them but they aren?t as thin as the called out washers.

Once I get how tight nailed down I?ll safety wire.
 
turns out there is no spec. Tight enough to hold it on but not so tight as to ruin the fiberglass. Then lock wire to keep the nuts from backing out.
 
Torque on fiberglass ?value?

There are a very few places on the plane where torque is not applicable. Fiberglass is one area that needs firm tightness that will hold but not crush the fiberglass. The nuts are also safety wired. So the answer I always give is a mix-mash of German/English ?torque? that I call: Guttentight ! 😂

Remember, you will need to align the holes on the thread end of the bolt with the holes in the nuts.

Enjoy your project! But that snorkel was not a great fit between the items at both of it?s ends! I don?t look forward to EVER taking it off!!!!
 
I didn't have any holes in the nuts; my throttle body was tapped and the bolts just went into the tapped holes. Then I wired the four bolts in right and left pair.
 
turns out there is no spec. Tight enough to hold it on but not so tight as to ruin the fiberglass. Then lock wire to keep the nuts from backing out.

One guideline you might use is the tensile strength of gelcoat (~11000 psi) or epoxy (~12000 psi) which would put the spec in the vicinity of 6 in*lbs for AN3 or 12 in*lbs for AN4 in excess of any running torque. Since it is not at all easy to measure such low values with any accuracy, one good way to get "close enough" is to calibrate the clutch on your electric screwdriver using a long extension and a bathroom scale.

Also, loctite is your friend, as long as you make sure bare metal is exposed on at least one surface.
 
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