Sloppy wing root pins

[vetdrem]

We are talking in the .001-.002 play. Like I said, not bad, but worth watching. I did check to determine where the wear is occurring, and I am sure that it is the holes in the spar. The pin is as smooth as new, the carry-thru has 5/16"ID tube welded to it for the pin to go through and it is nice and snug. The only "excessive" clearance is in the holes in the spar.

Lacking a spec to compare it to, I'll just keep an eye on them and when I think it is time, I'll probably build a collar to around the end of the spar. I think that it will be a snap to build and install one.

Louie

[mr bill]

How will you attach the collar to the spar?

[vetdrem]

I haven't thought it through yet. I would think that a steel collar that fit snuggly around the spar, drilled the right size for the pins, and pop riveted to the spar should do the job.

I'm really early in the process, and will probably change my plan a dozen times before I actually start fabricating anything.

Louie

[PapuaPilot]

If play is only 1-2 thousandths that isn't very much. You might try new pins or a close tolerance NAS bolt, if there is a way to keep it in.

If it gets to be too much would the next bigger size pin work?

[Paul Z]

I would have to guess that is within tolerance for the pin. If I look at the Mil-Spec for Fasteners .005 to .006 is the Major diameter tolerance. However, like I said I would have to go look up the Mil Spec for the Pull Pins to determine the allowable tolerance.