Bolt threads tested to failure

[3DDave]

Just an interesting video showing qualitative failure of bolt threads forced through a nut in compression.

 

[desertfox]

Hi Dave

Did you mean to post a link?

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[3DDave]

I thought I did put a link;

https://www.youtube.com/watch?v=VJipVCPd2nk

Daisy, Daisy, give me your answer do ...

 

[r6155]

This test is invalid. It is not under any standard test.

Regards

 

It is not under any standard test.

No but it's a fun test, which I think was the point.

Threads sheared off at the base, sweet!


"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[3DDave]

It seems to me like the bolt diameter increased just a little bit before the threads failed and that the exposed bolt thread pitch decreased just a little bit. Still too lazy to look up what the expected tensile strength of the fasteners should be.

What was most interesting is the nuts had enough rigidity that they didn't appear to expand before the threads failed.

I'm a little interested in this because of the recent commercial jet landing gear failure where the maker allows a major fitting to be re-threaded as long as a matching mating nut is used. Spoiler: the matching mating nut was not used.

Unlike these examples where a fairly clear coil of thread was sheared off, the fitting and mating nut involved in the failure had barely any damage and looked as if they could have been reinstalled to the before-separation condition to fail again another day. I tried to imagine a similar function fitting that would either obviously be incorrectly installed or would be correctly installed, but the ability of people to get past fool-proof designs was not overcome.

A tensile test to failure would have been more typical, but I suspect it would usually have ended with the bolt snapping and leaving the threads intact and therefore not as interesting.

 

[Tmoose]

Looks like few of the tests used the same type nut with bolts of differing goodness. So some were just repeat tests of the weaker nut thread strength.

Some ISO theories of proper mis=matching nut strength to bolt strength is contrary to commonly held beliefs in the US it seems.

And the chance for the shank to neck and fail before the threads was denied.

But certainly fun.

 

[SSCon]

It's actually pretty damn close to the standard proof test for nuts, just needs a hardened mandrel in place of the bolt.

Due to that the failures are about 10% below the standard proof loads for nuts (bolts failing first).

 

[r6155]

Wasting time.

Regards

 

Yeah but it's wasted time that has been monetized. Which apparently is all that matters these days.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Rogue909]

What standard test would this be in violation of? I've not heard of a proofload test designed around putting a bolt in compression. This isn't a tensile proofload of the bolt (skidmore or equivalent). This isn't proofloading a nut.

As best I can tell; this is an experiment. A near-useless (bolt don't usually get put in compression from my experience and the results were as expected) but fun and semi educational to the layman demonstration of thread failure.

The other videos in this series are trying to determine how many crushed pepsi cans to be put in a pringles can. Discussing which standards are at play may be reading (watching?) too much in to what is to be gained from the channel.

 

People, it's youtube! Do you expect code compliance?

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."