Edge margin for holes in Lugs

Try here:

David Merrill

I followed the NASA link. It _may_ answer the question - if I can interpret it correctly? :)

Thanks, David. That was quick too!

Richard

Hey Richard,

You did not specify, and I assume that you were interested in smaller than this, but I stumbled across the following in a small handbook I picked up the other day, called "IPT's Metal Trades Handbook". It was in the section on Structural Steel

___________________________________ Safe Edge Distances for Holes In Structurals

---------------------------------------------------------------------- Hole size | Edge Distance 9/32 | 3/8 11/32 | 1/2 7/16 | 5/8 9/16 | 7/8 11/16 | 1-1/8 13/16 | 1-1/4 15/16 | 1-1/2 1-1/16 | 1-3/4

-------------------------------------------------------------------- Table #64. Structural Edge Distances

Take care.

Brian Lawson, Bothwell, Ontario.

ps.......DID you find what you wanted, and if so, where?

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX >David Merrill wrote:

I think so, David.

The argument is that the rivets in my airframe don't quite meet the edge margin for thin sheet. This truss is built from 3/4x3/4x1/8" extruded 6061-T6 angle material, using 1/8" to 3/16" AD470 (driven) rivets. This is 5 times the normal .025 sheet thickness - with two pieces making 1/4" grip length.

The aero purist insist is is going to crack at the rivets (although with over

Even in an accident, the angles bend some, but no broken rivets.

I was trying to find something that would explain this, and the NASA document seems to help. Edge margin for lugs seems to be defined in part by the thickness of the part - with thicker parts requiring smaller margins.

That table above, if I'm reading it right, seems to agree(?)

Anyway, that's what the question was about.

Got a spare clue?

Richard

Pardon me please for missing the correct name, BRIAN!