PaulBuz
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| posted on 27/3/03 at 06:39 PM |
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Stainless bolts
Went to buy my new stainless bolts today, for the front wishbones.
On inquiring I was told that they are NOT high tensile bolts (ie 8.8 etc) in fact the chap said that were basically the same spec as mild steel, only
slightly harder.
I ended up getting BZP 8.8's.
Thing is how many of us are driving around with stainless bolts, thinking that all is well?
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chrisg
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| posted on 27/3/03 at 06:45 PM |
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I've never seen stainless bolts of grade 8.8, although I'm not saying there aren't any, I think most people know not to use
stainless in very high stress situations. worth repeating tho.....
Cheers
Chris
Note to all: I really don't know when to leave well alone. I tried to get clever with the mods, then when they gave me a lifeline to see the
error of my ways, I tried to incite more trouble via u2u. So now I'm banned, never to return again. They should have done it years ago!
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Lars
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| posted on 27/3/03 at 08:20 PM |
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i just bought some bolts, from namrick which are high tensile, but it says they are grade s.
What is the difference between that and grade 8.8?
I take it they are strong enough as they make them for cars.
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Mark Allanson
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| posted on 27/3/03 at 08:46 PM |
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'S' grade is the imperial version of 8.8 (metric) There is no High Tensile version of stainless
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stephen_gusterson
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| posted on 27/3/03 at 11:47 PM |
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we use a lot of stainless bolts where I work.
I asked this question of the supplier when he came to top up cos, one or two might find their way elsewhere.......
I cant remeber the grade but I was told they were fine for my application and that they used stainless in a car they raced.
atb
steve
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Rorty
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| posted on 28/3/03 at 01:46 AM |
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Bolt Grades and Classes are often confused, especially Grade 8, and Class 8.8.
Class 8.8 is almost the equivelent of Grade 5.
Imperial fasteners use Grades i.e. "Grade 5 or 8". Metric fasteners use Classes, i.e "Class 8.8 or 10.9". They are not
interchangeable.
Just for comparrison, Grade 8 = 150,000 PSI, and Class 10.9 = 1034 Mpa, which are as near equal as makes little difference.
The bolts commonly used to fasten on CV joints are Class 12.9...tough little ba$tards.
Grade 8 are ideal for suspension mounts, and Grade 5 are OK for just about everything else on your Locost.
Just don't buy any fasteners less than Grade 5, and you won't be tempted to use them in a critical location.
The highest grade of stainless fastener is 316-80, which is only about 116,000 PSI, and Grade 5 is about 120,000 PSI.
If you are using stainless fasteners with stainless nuts, you should use a lubricant compatible with stainless, as stainless threads can easily
"gall", causing them to seize.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Liam
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| posted on 28/3/03 at 09:22 PM |
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Bonjourno
I bought a load of stainless bolts from Newark show last year - various sizes. They all say 8.8 on the heads which I assumed was the grade (or class
or whatever). What does it mean then? As well as the sizes, the labels on the plastic bags say '8.8 hexagon sets'. Que?
Liam
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Mark Allanson
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| posted on 28/3/03 at 10:11 PM |
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It says 'India' on bus tyres, but I've never known one to go that far!
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Viper
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| posted on 28/3/03 at 10:53 PM |
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quote:
Originally posted by stephen_gusterson
we use a lot of stainless bolts where I work.
I asked this question of the supplier when he came to top up cos, one or two might find their way elsewhere.......
I cant remeber the grade but I was told they were fine for my application and that they used stainless in a car they raced.
atb
steve
Stainless in a race car????
we certainly don't use them in any of the cars we run simpley because of the weight.
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stephen_gusterson
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| posted on 28/3/03 at 11:43 PM |
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thats interesting......
as you know Viper, I work for a company that makes x-ray machines. Cos of this I am involved in stuff like density (SG) of metals and other
materials.
Stainless steel measures under x-rays, and is quoted in tables, as being near as anything the same as mild in density - in fact most common metals
have a density between 7 and 8.
The physics seem to show that a stainless bolt weighs very close to a mild steel one.
atb
steve
[Edited on 28/3/03 by stephen_gusterson]
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macbrew
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| posted on 28/3/03 at 11:54 PM |
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Mark started it !!!!
Says BISTO on Buses but they don't sell it !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Viper
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| posted on 29/3/03 at 12:06 AM |
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One s/s bolt v one m/s bolt the difference would be un noticable but over a whole car? as an example pick up an 8x4 sheet of 10swg m/s then the same
in stainless and then tell me there is little difference. Oh and another point to bear in mind stainless tends to bend a lot easier than mild steel,
on the Tuscan we run we use a lot of aircraft spec K nuts and alloy bolts in non load bearing areas and we have managed to save a lot of weight, so
much so we had to add weight to bring it up to the minimum allowed. I would be very surprised to see any race car using stainless bolts, i can't
see any advantage, granted on a road car i can see the point in areas that don't often get looked at, but on a properly maintained race car
every nut and bolt gets inspected and re tightened after every run, i would be interested to know what car and class they raced...
Rorty, i believe you are into buggies, a car that is run in probably the most inhospitable eviroments, do you use stainless fixings? and if so
whereabouts?
Oh and i know there are different grades of s/s as there all metals but in my opinion, and this is just my opinion, s/s should never be used in a load
bearing enviroment. (excepting foodstuffs etc).
of course i could be talking total billox and i am sure some one will be kind enough to tell me so.......
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Rorty
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| posted on 29/3/03 at 04:09 AM |
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Liam:
quote:
I bought a load of stainless bolts from Newark show last year
Therin lies the problem! Fasteners are one of the easiest areas for cheap fakes to pervade. I was offered a "CV kit" from a Halfrauds type
store over here one week end, when a M8's race car had a mishap. The cap head bolts were stamped "12.9" on their ends, but on the
back of the bubble pack, it said made in Taiwan. I borrowed a hammer from the store owner, and proved to him the bolts weren't Class 12.9!
Viper:
quote:
Rorty, i believe you are into buggies, a car that is run in probably the most inhospitable eviroments, do you use stainless fixings?
I only use stainless for crush tubes, and occasionally for brake discs. It has little use on a car.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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darren(SA)
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| posted on 29/3/03 at 04:01 PM |
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I dunno how relevant this would be to this topic of s/s bolts compared to mild steel bolts but here goes anyway:
One of our suppliers (laser cutters) said something interesting to me the other day,
A 16mm thick stainless sheet would require the same settings to cut as 25mm mild steel sheet on his machine(30 bar nitrogen or something like
that).
Does this mean that s/s is 64% stronger than mild steel?
cheers
darren
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gjn200
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| posted on 29/3/03 at 05:15 PM |
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No, it's harder, not tougher and hence more brittle, ie it cracks easily. Thats why if you get a ss exhaust and look after a bit it appears to
be going rusty! They have to use a crappy type to stop it falling apart.
<- Me!
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Mark Allanson
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| posted on 29/3/03 at 05:15 PM |
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No, its just got a higher melting point
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dmottaway
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| posted on 29/3/03 at 10:51 PM |
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stainless steel
over on TOL, Drr. Hess made his entire frome from S/S tubing. Is this a bad thing?
dave
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Peteff
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| posted on 30/3/03 at 01:46 PM |
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Stainless steel isn't always.
I used to work at an IMI foundry where stainless steel was made. They sold steel to countries all over the world. Kanematsu Gosho was one firm in
Japan who they supplied. The grades all had AISI numbers, like 316 and 304 etc. I used to load them into containers for transportation and I noticed
that two of them,I think 431 and 416, which were used to make reinforcing bar both used to surface rust when exposed to atmosphere. I also remember
that the scrap bins were divided into magnetic and non magnetic and 18/8 was a general term used for non mag scrap, which was sold off to cutlery
firms like Viners.
yours, Pete.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Jon Bradbury
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| posted on 2/4/03 at 03:48 PM |
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This is getting technical...
I asked my bolt supplier (a local shop in Worthing called "the Nut House", appropriately enough) about s/s bolts and he said they have a
lower shear value than 8.8 steel bolts... Anyway he didn't recommend them for the front suspension mounts - so I bought plated 8.8 bolts
instead.
[Edited on 2/4/03 by Jon Bradbury]
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Rorty
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| posted on 3/4/03 at 04:32 AM |
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Not wanting to put a downer on you, only thinking of your safety, but did you check the "plated" bolts were post treated? Depending on the
type of plating, the bolts may suffer from hydrogen embrittlement.
If the fasteners are boxed, and from a reputable manufacturer, chances are, they're alright. It should say so on the box.
I always make sure any custom plating I have done comes with a certificate of post treatment by the plater. It's easy and cheap to do.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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