Hi Guys
I`m picking up on my book Locost build after 2YR layoff due to other projects. Where was I? Yeah I have 9.5mm bolts which go through my Herald
bushes.On the head of the bolt it reads ORSB1 S1. Are these bolts strong enough as I`ve made all wishbones etc. Started this project 4yrs ago and am
amazed how it has all moved on as far as availability of suitable components goes. I spent an inordinate amount of time making stuff that you can buy
so cheaply now.
Thanks in advance
Lexi
always good to pickup the past,
bus please consider to go for PU bushes
unless you'r willing to chance the herald one's every year because the wear out very fast
Thank you my young Dutchman! Yeah I`m not a fan of PU and i would have to change steel bushes at the end of my wishbones panhard trailing arms. I know
that bolts are coded for strength and wondered if anyone knew the meaning of the code on my bolthead. Been that long since I bought them.
Alex
Nice to see another crossflow on its way. Re bushes, you probably have 3/8" UNF bolts through the bushes, as for the markings, can't help
I'm afraid.
I dont think you're stuck with rubber bushes though, I've seen replacement Herald bushes in PU from Supaflex I think.
Marcus
Hi mate
If in doubt replace them with Hi tensile bolts and or contact your local fastner suplier he will be able to tell you what grade of bolt that you have
.
best wishes
Iain
5th thread along simular lines in a week. I bought 20 PU bushes, from TRGB links on a previous thread just add .co.uk though for less than £80 with vat and shipping. standard herald replacement so will fit.
Thanks guys
Top forum!!
Lexi
Is ORSB1 S1 the only identification on the head, is there no other markings like lines or numbers?
The common markings are a number of lines radiating out (eg 3 lines going out from the center) or a stampes number with one decimal place (eg 8.8 or
10.9).
Every high tensile bolt sold in the UK should have a marking on its head; if it's a plain head do not use it.
The markings can consist of either letters (UNC, UNF and Whit. threaded bolts) or numbers (Metric or ISO Metric). The letter to look for is
'S' or a higher letter(imperial), or the numbers 8.8 or higher (metric).
For the technically minded, the 8.8 designation is two separate numbers. The first '8' is the tensile strength, i.e. the load at which the
material begins to fail, given in units of 100MPa or MN/m2, giving 800 MN/m2 or 800,000,000N/m2. Convert this to kg by dividing by gravity (9.81m/s2)
say 10, to give 80,000,000kg/m2, and then divide by 104 to convert to cm2 which gives 8000kg/cm2 or 8 tonnes/cm2. The second part of the designation
'.8' is then used to generate a decimal fraction of the first part, i.e. 8 x 0.8 = 6.4 or 640Mpa, 6.4 tonnes/cm2. This is the yield
strength, i.e. the load at which plastic deformation of the material occurs.
Stainless steel bolts usually have a tensile strength of 5 Tonnes/cm2, 33 tons/in2 (marked A2 for Stainless Steel and 'M' for the strength)
so be warned! Some bolts may be marked in Newtons per square centimetre, in which case high-tensile means over 80N/cm2. Do not get confused with the
manufacturer's name code, e.g. GKN, SN, BP, etc.
Although it is a good and worthy thing to buy the very best quality bolt for the job, aren't we overlooking one very important factor?
The suspension arms, bolts and bushes are held onto the chassis with pieces of 50mm wide, 3mm thick mild steel strip. From the rim of the bolt-hole
to the edge of the steel strip is probably 10 - 15mm. I would suggest that this steel strip is likely to fail long before even a middling-quality bolt
gives up.
At a guess, I would suggest that what we should be looking for in a bolt is toughness, i.e. a resistance to shocks and a lack of brittleness.
It is certainly a good idea to buy good quality bolts from a known supplier as there are a lot of Far East bolts around that are pretending to
be high-quality items, but may well prove to be treacherous in use.
For more info, see Carroll Smith's book on bolts & fasteners, or read the stories about aircraft crashes caused by 'cheap'
fasteners that failed in service.
For myself, I bought 'AN' quality nuts and bolts from a reputable aircraft parts supplier (partly for 'known source' issues, but
also because I was able to specify the length of the unthreaded shank). Otherwise, I would have looked for big-name branded products from an
engineering supplier.
rgds,
David
Was plucking up currage (spelt wrongly) to ask this anyway, but what is the tensile rating of an A4 SS bolt, and how does that compare to an 8.8 HT?
Bearining in mind the SS shouldnt rust.
Even though rorty has been opinionated in his choice of cars, he comes in handy! Cheers for all the info guys, made a daft question very easy to ask!
See this handy little table for tensile strengths of stainless bolts
http://mdmetric.com/fastindx/t28u.pdf
Call me thick, but what does that mean?
quote:
Originally posted by JamJah
Even though rorty has been opinionated in his choice of cars....
INCOMING!
quote:
Originally posted by Rorty
quote:
Originally posted by JamJah
Even though rorty has been opinionated in his choice of cars....
Pardon?
Thought you got in trouble with the catherham forum. Wasn't having a go. Guess no one actually knows what that table means.
The table has quite a bit on it you dont need to know.
You are really only interested in the steel grade (second column) and the tensile strength in the bolts column.
Tensile strengths of stainless bolts vary from 500 to 1000N/mm^2 depending on the exact material.
For your bolts 316SS A4 the tensile strength is about 700MPa. Compared to 8.8 steel bolts which are about 800MPa as Rorty said. Not a huge
difference...
(See the chart here: http://www.assda.asn.au/asp/index.asp?pgid=18732)
David
[Edited on 12/4/05 by flak monkey]
[Edited on 12/4/05 by flak monkey]