On May 18, 11:45*am, JJ Sinclair wrote:
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- Hide quoted text -

- Show quoted text -

JJ: I don't think that the big bolts are shearing off. They are
breaking due to a gradual fatigue process in tension. What I'm
thinking is that it is the fore and aft forces due to road bumps and/
or washboard acting against the inertia of the top that is putting the
cycled load on the bolts that eventually is their unduing. The
fatigue thing was definitely confirmed by Howard Banks based on the
observations on Andy's broken bolt. When you said yesterday that you
checked your bolts, did you really check them for incipient fatigue
damage?

Very interesting that there are sheared rivets going on as well. I'll
have to look for that too.

GW