[Healeys] Tightening bolts

[Bob Spidell]

It's not, or shouldn't be, friction on the threads that holds a bolted 
joint together; it's the loaded tension of the stretched bolt. For any 
bolted joint potentially exposed to moisture, with a few exceptions*, 
anti-seize is appropriate. Common (cheap) anti-seize, which uses ground 
ceramics, is OK for non-high-temp applications; copper-based is better, 
and nickel-based is best for high-temp applications (ex. EGR valves, 
spark plugs, etc.).

Like Mirek, and after much thought, I've taken to carefully putting a 
bit of A-S on brake fitting threads. Maybe it's newer (lack of) quality 
fittings and cylinders, but in the brake work I've done recently the 
fittings haven't screwed-in as easily as I think they should, and we've 
all probably rounded the 'nut' on brake fittings that have gotten 
corrosion-welded in place (requiring cutting and replacing the line and 
possibly the cylinder). Note brake fluid shouldn't ever come in contact 
with the A-S, if the BF is getting past its seal that has to be 
addressed properly.

Fasterner 'science' is fascinating

Explained well here:
https://www.google.com/search?client=firefox-b-1-d&q=bolt+fastening+theory#kpvalbx=_IzREY-bKO43ZkPIP16m4qAE_44

More:
https://en.wikipedia.org/wiki/Bolted_joint

* Where I don't use A-S, I may use threadlocker (usually blue, red for 
inserts). I can't make up my mind on wheel studs; A-S for easy removal, 
threadlocker for 'security' or nothing. Note both A-S and threadlocker 
will affect bolt/stud tension for a given torque value.



On 10/10/2022 5:04 AM, m.g.sharp--- via Healeys wrote:
>
> Hi Simon, I often use an anti-seize paste on threads and I have never 
> had a fastener loosen off and it definitely aids removal later.  For 
> example, One common component to seize is the capillary tube where it 
> goes through the nut on the temperature sensor.  For decades I have 
> coated the tube where it passes through the nut,  as well as the 
> thread, and it makes removal of that nasty little thing so much 
> easier.  Mind you, it is a tapered pipe thread and they tend to stay 
> tight.  Another instance is brake line fittings; I slide the fitting 
> back, lightly coat the brake line and then slide the fitting up to the 
> flare, and coat the threads on the fitting, taking care not to get any 
> into the hydraulic circuit.  I have never broken a brake line from it 
> seizing in the nut after doing this. I use “Copper Anti Seize” made by 
> Permatex.
>
> Cheers, Mirek
>
> *From:*Healeys <healeys-bounces at autox.team.net> *On Behalf Of *Simon 
> Lachlan via Healeys
> *Sent:* October 10, 2022 7:30 AM
> *To:* 'Healeys' <healeys at autox.team.net>
> *Subject:* [Healeys] Tightening bolts
>
> I had to loosen the bolts attaching the hinges on my BT7 the other 
> day. 6 of them turned quite easily after some fairly hefty initial 
> work. One needs a couple of whacks with an impact driver to get it 
> started and one was just plain loose.
>
> So, now I want to tighten them up. Plainly, I want to be able to undo 
> them again at some time or other….
>
> Does the team think that something like Coppaslip (or whatever it’s 
> called) is a good idea. Half of me says, “Use it. You’ll be able to 
> tighten them up that little bit more while still being able to undo 
> them later”.
>
> And the other half says, “Don’t use it. It will enable the bolts to 
> loosen themselves off.”
>
> Which half of me is right???
>
> Thanks,
>
> Simon
>
>
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