Cross-threaded rear wing bolt hole

[tommyg]

I have managed to cross-thread one of the holes that my wing attaches onto and wondering if any tips of how to get the bolt in or out?

Firstly not a major issue, as the wing is very firmly attached with all of the other bolts, so this is just to get is absolutely right (I like to do a proper job).

The bolt is the one right at the bottom at the front of the rear wing.

I have managed (!) to cross-thread the bolt so it is only half in, but now it will not bind to either come out or go in further.

Any ideas on how to either get it to bind in, or how to get it out, so I can try again?

[Jonathan Kay]

What's the female bit on that one... something like a RIVNUT?

Jonathan

[tommyg]

Yes, exactly, like a rivnut inserted into the body side.

[Jonathan Kay]

There are others with much more experience than me. But while we're waiting... the priority must be to not damage the skin. Do you have access to the back so that you could grind the flare of the RIVNUT off? Might need a bit of cooling.

Jonathan

[tommyg]

No easy access to the back to grind as the wing gets in the way.  Perhaps 10cm gap only as the bolt is still in place.

[shn7]

Can you get something under the bolt head to help pull it out whilst unscrewing it? That might just allow you to extract it.

[Jonathan Kay]

Can't picture the access. Mole wrench on the back of the RIVNUT so that you can get counterforce there rather than on the skin?

Jonathan

[tommyg]

Thanks both

Yes, tried leveraging the back of the bolt with a paid of pliers whilst unscrewing - that did not work

Cannot get to the back of the rivnut as within the body.  I might try tonight to see if there is enough space to grip the front of the rivnut.  Small damage to the skin paint there should not be an issue as covered by the wing....

 

[Jonathan Kay]

The one I hate doing... cut the bolt flush and drill down the shank to destroy it?

Jonathan

[tommyg]

Yes, that may be the ultimate solution!

[CharlesElliott]

I assume that the rivnut is now turning in the skin, as even with a cross threaded M5 bolt, you should be able to undo it easily. The rivnuts are aluminum so the threads will not hold up to any abuse.

First option is as you suggest, try to get some pliers or small mole grips to hold the head of the rivnut.

Otherwise just cut the screw off, and try option 1 again.

When the bolt is out, you'll probably need to drill the rivnut out and replace it. Or just leave it as it is. On my race car, I only tend to use 3 bolts to hold the rear wings on.

[tommyg]

Good news, managed to get the bolt out with a quite a few "technical taps" with my rubber hammer!

Now need to work out what to do with the rivnut.....trying superglue to see if that gives enough friction to get it going, then may leave it out.

Thanks for all of the help!

[Jonathan Kay]

I'm lost... is the RIVNUT still in the skin, and is it spinning freely?

Jonathan

[Paul Deslandes]

if you can get to the outer of the rivnut, can you punch the rim to lock it in place at, say, 3 x 120deg intervals, using a hammer and punch or an automatic centre punch? As it's been crossed, you'll need to clean the thread with a tap (M4?).  Or drill the top off and let it float around inside and replace with a new rivnut.