Nuts and Bolts

[Richardnew]

Here's a copy of an article I did for Vintage Motorsport a few months back. It's more than anyone really needs to know about nuts and bolts. Enjoy.



Richard Newton
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[chris_seven]

Richard,

I can only see a single page with this link and I think that some further explanation between stretch, strain and stress is needed for the sake of clarity.

There are a few other points that I would like to debate and would welcome the opprtunity to have the 5 minute argument or even the full half an hour, (apologies to Monty Python).

The correct use and understanding of fasteners is a subject in which I have a significant interest and even 'Nuts, Bolts, Fasteners and Plumbing' has a few inconsistencies.

[Kris Clewell]

You could really get OCD about this stuff, thats for sure!

[Richardnew]

The article was so long that I had to cut it into two sections. The problem is where do you stop with this stuff? It's big time OCD material. The good part is that the folks at ARP liked the article well enough to link it to their web site. The 2nd section will be posted in a few days.

Richard Newton

[Kris Clewell]

The article was so long that I had to cut it into two sections. The problem is where do you stop with this stuff? It's big time OCD material. The good part is that the folks at ARP liked the article well enough to link it to their web site. The 2nd section will be posted in a few days.

Richard Newton

I would say stop when it prevents you from appreciating what you've put together. We aren't working on the space shuttle after all... if something breaks we likely aren't going to burn up in the atmosphere.

[motogman]

... if something breaks we likely aren't going to burn up in the atmosphere.

Certainly true but it usually takes me a whole lot more time and some busted knuckles fixing what it is when I break something (in this case twisting off a bolt or some such thing).

There are a few other points that I would like to debate and would welcome the opprtunity to have the 5 minute argument or even the full half an hour, (apologies to Monty Python).

I appreciate Richard's article and the effort to maintain & share knowledge on this topic. I also had some points to debate... is this the right place to do that? If so let the OCD obsessions begin....

[chris_seven]

if something breaks we likely aren't going to burn up in the atmosphere.

True, but fatal injuries can still occur due to poor fastener application even at mundane traffic speeds and certainly on the race track.

The condition and treatment of 50 year old bolts on restored performance cars may also be something we should give the correct amount of attention, specifically with regard to thread condition, cleaning methods and re-plating.

I am sad to say that the article, thus far, isn’t more than I would need to know about fasteners.

I hope that the difference between strain and displacement (stretch) is outlined in Part 2.

I also think some comment about the probable variation in preload that can result from ‘torque tightening’ would be helpful in understanding why care is needed.

The variation in stretch suggested is 0.0055” to 0.0065” is, of course, a variation in preload of approximately 20% which itself is not insignificant and is possibly too much.

Finally, I would never use a thread chaser on any new fastener that was used in a critical application or was a Grade 8.8 or stronger. The effects of such pieces of equipment on thread finish are generally uncontrolled and they can have an unpredictable effect on the torque/tightness of the fastener.

I apologise for my OCD but I do believe these basic points need discussing.

[Richardnew]

The whole purpose here is to bring all of this into the conversation. The reason I did the article in the first place is because no one talks about any of this. Vintage Motorsport magazine is nice enough that they let me go off on these rather obscure topics that never get discussed anyplace. I do have space limitations though.

An interesting thought is how expensive all the really good hardware is. Then if you do some calculations regarding the difference between the hardware you get at the local big box and ARP (for instance) it's not that big of a deal - considering the total car expense. I will say I was a little taken back at the cost of studs for my 911 though.

I welcome this discussion. Thanks.

Richard Newton

[Kris Clewell]

True, but fatal injuries can still occur due to poor fastener application even at mundane traffic speeds and certainly on the race track.

you mean like this. there's far more to fastener application than torque stretch etc. using the proper fastener at the proper time is really important to I think...



This kind of stuff is absolutely definitely important. Torque saves lives, and engines, but I certainly am not going to be doing any mathematical calculations. I'd rather be driving, and I never took math in college. I've bought ARP stuff for high boost applications in the past. I saw how much they were for a 911 and fell out of my chair laughing. Not a chance it's worth it for me.

[Richardnew]

This has turned out to far more popular than I could have imagined. Just for your own interest here's a history of fasteners.

Richard Newton