Cobra top hinge plate bolt failure

On May 18, 10:23*am, Andy wrote:
On May 18, 9:44*am, Steve Koerner wrote:

I have 3 Wing Riggers that I need to get shipped out today, but as
soon as I get a chance I intend to investigate changing the bolts to
the next larger size, 3/8" grade 8. *Of course that will mean drilling
the holes larger and it will also mean that the head will not be
neatly counterbored into the handle. *If that plan works out, I will
post back here.

GW

I'd be interested to hear how that works out. *There is a least one
spacer block inside the frame extrusion and it looks like it would
have to be extracted, drilled, and replaced. *There may be two each
side. *Given the limit access to the extrusion opening it could be a
bit awkward to work the inner blocks.

If I was going to larger bolts I think I'd relocate the handles and
keep them on 5/16 socket cap bolts. *They wouldn't need the spacer
blocks as long as a moderate torque was used.

Andy (GY)

The plot thickens, I moved both wings aft in order to get a good look
at the forward corner of the fiberglass top. The top has an aluminum
rail where it meets the lowar trailer and this "L" member overlaps the
cross member (where the hinge plate is bolted). There are 4 large
aluminum rivets on each side that bind these members together. Well,
all 4 rivets on the right side were sheared off and 2 on the left side
were sheared off! The forward 'shove' from the struts would try and
shear off these rather weak fastners as they are loaded in "shear".
The thing I don't understand is why the large steel bolts are shearing
off, because they are not loaded in shear?
I replaced the corner rivets with 1/8" steel rivets.
JJ