182P seat rail replacement

Here's something: https://www.mcfarlaneaviation.com/media/documents/ce-90-03r2.pdf

I have to take back what I said about not using 60KSI screws. In that SAIB we read:

Since it is difficult to install many of the rivets required to attach the seat rail, it is permissible to
substitute screws with ultimate tensile strength exceeding 50 ksi. Example of such screws are
AN515, AN520, AN525, MS35206, MS35207, MS35214, MS35215, MS35218, MS35219,
MS51957, or MS51958 with lock nuts provided the holes are ream fit and spotfaced.

Note, though, that spotfacing is required for screws, as I said earlier. The sloped surface of the rail flange is not suitable for the screw heads.
 
A slightly sloped surface under the head wouldn't bother a soft 60ksi screw - but it can't be adequately wrenched (yielded) from the head end.
 
Maybe it isn't the rail or screw that is the issue. How do you get a screw or CR rivet on a sloped surface to fit into a straight hole? Maybe it is the hole in the under lying structure that should be cared for?
Maybe that is why spot facing is asked for?
 
JAWS said:
Maybe it isn't the rail or screw that is the issue. How do you get a screw or CR rivet on a sloped surface to fit into a straight hole?
Click to expand...
it is called a spot face, they come in different sizes and different pilot sizes.

look it up, it isn't that hard.

Piloted spot face
 
JAWS said:
Maybe it isn't the rail or screw that is the issue. How do you get a screw or CR rivet on a sloped surface to fit into a straight hole? Maybe it is the hole in the under lying structure that should be cared for?
Maybe that is why spot facing is asked for?
Click to expand...
The flange of the rail is pretty thin relative to the hole diameter..maybe 1/8". The skin beneath is .025" or .030. The underlying structure isn't that thick either except at the gear box and strut carrythrough. The spotfacing is to get the screw head seats and nut seats parallel to avoid bending the screw or ending up with just edge contact that will result in the hardware coming loose as the aluminum indents.
 
Dan Thomas said:
The flange of the rail is pretty thin relative to the hole diameter..maybe 1/8". The skin beneath is .025" or .030. The underlying structure isn't that thick either except at the gear box and strut carrythrough. The spotfacing is to get the screw head seats and nut seats parallel to avoid bending the screw or ending up with just edge contact that will result in the hardware coming loose as the aluminum indents.
Click to expand...

You don't say? o_O

Thanks for clarifying.
 
I appreciate everyone who contributed to this thread. It was very helpful. My A&P and I are riveting in McFarlane left seat rails this weekend.
 
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