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Nuts

Posted: Mon Jul 16, 2007 12:23 pm
by Hambo
Is ther nuts and bolts for the suspension in the Elise parts,
Full stainless steel nut and bolt kit.?

Re: Nuts

Posted: Mon Jul 16, 2007 12:26 pm
by Rich H
Hambo wrote:Is ther nuts and bolts for the suspension in the Elise parts,
Full stainless steel nut and bolt kit.?
Eh?

Get 8.8 bolts and nylock nuts from your local nuts and bolts supplier. I would rather break a bolt than uprate the bolts and break something more important!!

Stainless may well be too brittle to cope.

Posted: Mon Jul 16, 2007 12:52 pm
by robin
Yes, you absolutely do not want to use SS on your suspension parts (unless the manufacturer designed it that way, of course, but I doubt you'll find such a thing).

To protect against corrosion, copper slip the shank before fitting, then tighten the nyloc, then copperslip what's left. It will rapidly attract crud, so will look corroded, but actually won't be.

You can get bolts that are treated to prevent corrosion, but commonly not in 8.8 and below.

For the hub-to-plinth bolts there has been a whole load of debate recently and in the end Lotus have suggested using a 10.9 cap head bolt, even on the alloy uprights (though in this case, still torqued to the 8.8 spec torque - this implies that you need to check them frequently).

Cheers,
Robin

Posted: Mon Jul 16, 2007 3:07 pm
by hendeg
robin wrote:Yes, you absolutely do not want to use SS on your suspension parts (unless the manufacturer designed it that way, of course, but I doubt you'll find such a thing).
There is a range of stainless steel bolts that are available in 8.8 and 10.9 grades (http://www.bufab-stainless.se/eng/index.htm). I can supply so PM me with sizes if you're interested.

You could also consider using Nordlock washers (http://www.nordlock.com) in place of nyloc nuts. How did you get on with them Lawrence?

Gary.

Posted: Mon Jul 16, 2007 9:49 pm
by robin
Interesting ....

Are these bolts guaranteed to behave in all ways like the 8.8/10.9 items they replace? For example, will the 8.8 variant bend in the same way a normal steel 8.8 bolt would bend when overloaded, or will they hold on longer without deforming and then break.

For the suspension parts, you really want them to bend first I think ... but then I am no expert!

Cheers,
Robin

Posted: Tue Jul 17, 2007 9:44 am
by hendeg
robin wrote:Interesting ....

Are these bolts guaranteed to behave in all ways like the 8.8/10.9 items they replace? For example, will the 8.8 variant bend in the same way a normal steel 8.8 bolt would bend when overloaded, or will they hold on longer without deforming and then break.

For the suspension parts, you really want them to bend first I think ... but then I am no expert!

Cheers,
Robin
They are designed to have the same Tensile and Yield strengths as their equivalent carbon steel bolts;

Tensile strength measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks.

Yield strength is the stress at which material strain changes from elastic deformation to plastic deformation, causing it to deform permanently.

So, they should perform exactly the same. There are variances when you get into high and low temperatures because carbon steel becomes more brittle. Even allowing for Scottish winters, I don't think it would have an impact on car parts :wink: .

Posted: Tue Jul 17, 2007 1:02 pm
by alicrozier
hendeg wrote:
robin wrote:Interesting ....

Are these bolts guaranteed to behave in all ways like the 8.8/10.9 items they replace? For example, will the 8.8 variant bend in the same way a normal steel 8.8 bolt would bend when overloaded, or will they hold on longer without deforming and then break.

For the suspension parts, you really want them to bend first I think ... but then I am no expert!

Cheers,
Robin
They are designed to have the same Tensile and Yield strengths as their equivalent carbon steel bolts;

Tensile strength measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks.

Yield strength is the stress at which material strain changes from elastic deformation to plastic deformation, causing it to deform permanently.

So, they should perform exactly the same. There are variances when you get into high and low temperatures because carbon steel becomes more brittle. Even allowing for Scottish winters, I don't think it would have an impact on car parts :wink: .

At the risk of being pedantic...not strictly true ;)

They can have identical Yield and UTS but different Youngs Modulus. To take an extreme example, if the bolts were Titanium (with the same Yield and UTS) the Youngs Modulus is approximately half that of Steel therefore would deflect twice as far for the same given load. (15 vs 30x10E6 psi)
They could also perform in a radically different manner from the yield point to eventual failure...

This is all theoretical codswallop however as in practical terms the modulus of carbon and stainless steels are as near as makes no difference. :D

Posted: Tue Jul 17, 2007 1:37 pm
by Rich H
Bet thay cost more than 10p each too...

I'll stick with 8.8 mild steel BZP thanks... :lol:

Posted: Tue Jul 17, 2007 2:11 pm
by YvoTuk
Can't speak for the kit EP is doing, but our kit sure doens't include any stainless replacements for suspension parts.

The kit we're doing is taken from my (old) personal website http://www.lotus-elise.nl where I listed all the nuts and bolts / washers etc. which I found on my car.

It's not a 'general purpose jobby' it's specifically for the S1 or S2 and from personal experience, I can say that it's really worth doing this.

As for the suspension bolts, I do refresh these from time to time. I'm actually looking into offering a kit of correct spec bolts for suspension parts.