andyace
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| posted on 23/9/05 at 10:16 AM |
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Bolt and Washers Specification
Hello,
Just looking to buy a load of nuts,bolts and washers for the build.
What spec should I be looking for, also should they be zinc plated, stainless?
Where is best to get these, Screwfix only seems to do sizes in multiples of 10, I may need a 25mm bolt for example.
I have looked at screwfix which for example has the following:
Bolts (Set Screw) M8 x 30mm
Set Screw x 100 = £3.35
A2 Stainless Steel Set Screw x 100 = £8.60
A4 Stainless Steel Set Screw x 100 = £18.36
Washers
Zinc Plated or Stainless?
Many thanks, Andy
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Rek
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| posted on 23/9/05 at 11:06 AM |
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Im using Namrick for mine as I need a whole load of Imperial sizes
www.namrick.co.uk
Ive been told High Tensile 8.8 zinc plated will do the job
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Fred W B
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| posted on 23/9/05 at 11:12 AM |
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I buy:
m6, m8 bolts in stainless -you can shorten them and the cut ends don't rust.
Larger bolts get expensive in stainless.
Flat washers always stainless, cheap and don't rust.
Nylocks always plated, stainless are very expensive, and plated does the job
fred
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BKLOCO
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| posted on 23/9/05 at 11:34 AM |
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For automotive work for everything that is remotely structural or in the drive train you should allways use high tensile 8.8 grade bolts as a minimum
spec. For certain items you need to increase this to 10.9 or sometimes even 12.9 a good example of this is the spline clamp bolt on the steering down
link. This definately needs to be 10.9 minimum. There are many other highly stressed fastenings on a car and common sense will usually give you a good
idea where these are. If in doubt looking at an equivalent area on a production car will generally give you a good clue.
A good source for screws although a little expensive is http://www.ebolt.co.uk/index.html
Stainless bolts are NOT high tensile.
The A2 A4 grading only refers to the corrosion resistance.
A2 General use ie. food industry
A4 Marine environment
[Edited on 23-9-05 by BKLOCO]
[Edited on 23-9-05 by BKLOCO]
[Edited on 23-9-05 by BKLOCO]
Experience is what you get when you don't get what you want!!! 
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ayoungman
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| posted on 23/9/05 at 11:45 AM |
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Remember, don't use stainless on anything like suspension. Its nowhere near as strong as high tensile bolts. Only use it for dressing up non
safety critical components. Afterall, we don't want anything dropping off do we ?
"just like that !"
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andyace
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| posted on 23/9/05 at 12:04 PM |
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Thanks for all the feedback,
Just another question. I am intending to use washers on the nut side of the bolt as I do not want to strip my nice powder coating off the chassis.
I am assuming this is ok, also could I put washers on both sides, particularly suspendion bolts.
Andy.
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BKLOCO
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| posted on 23/9/05 at 12:15 PM |
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General engineering practice dictates that you place the washer on the side that is being turned to tighten the fastening. ie if your holding the bolt
head still and turning the nut the washer goes under the nut and vice versa. there is generally no problem in putting washers on both sides. The only
"no no" is a plain washer with a spring washer on top of it. This does not make for a good shake-proof fastening.
Experience is what you get when you don't get what you want!!!
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Rorty
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| posted on 24/9/05 at 05:28 AM |
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quote:
Originally posted by BKLOCO
For automotive work for everything that is remotely structural or in the drive train you should allways use high tensile 8.8 grade bolts as a minimum
spec. For certain items you need to increase this to 10.9 or sometimes even 12.9 a good example of this is the spline clamp bolt on the steering down
link. This definately needs to be 10.9 minimum. There are many other highly stressed fastenings on a car and common sense will usually give you a good
idea where these are. If in doubt looking at an equivalent area on a production car will generally give you a good clue.
Stainless bolts are NOT high tensile.
There's no such thing as "8.8 grade bolts". The metric designation is Class 8.8 and the imperial designation is Grade 8, but they
are not remotely comparable in strength.
If using metric fasteners, choose Class 10.9 for highly stressed applications and Grade 8 for imperial fasteners.
High tensile stainless fasteners are available in 17-4PH stainless, but why bother. The zinc or cadmium plated steel fasteners wont rust away in the
time you own the 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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Mix
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| posted on 25/9/05 at 03:32 PM |
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I would have no reservations about using stainless bolts on a sevenesque suspension.
Admittedly, size for size, they are not as strong as high tensile bolts but they are only attached to 1.6mm ERW by 3mm mild steel brackets. I'd
put money on the bolt being the last thing to give way.
Mick (trying to keep things in perspective  )
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Rorty
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| posted on 25/9/05 at 09:40 PM |
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quote:
Originally posted by Mix
Admittedly, size for size, they are not as strong as high tensile bolts but they are only attached to 1.6mm ERW by 3mm mild steel brackets. I'd
put money on the bolt being the last thing to give way.
Mick (trying to keep things in perspective )
True.
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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BKLOCO
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| posted on 26/9/05 at 07:43 AM |
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quote:
Originally posted by Rorty
quote:
Originally posted by BKLOCO
For automotive work for everything that is remotely structural or in the drive train you should allways use high tensile 8.8 grade bolts as a minimum
spec. For certain items you need to increase this to 10.9 or sometimes even 12.9 a good example of this is the spline clamp bolt on the steering down
link. This definately needs to be 10.9 minimum. There are many other highly stressed fastenings on a car and common sense will usually give you a good
idea where these are. If in doubt looking at an equivalent area on a production car will generally give you a good clue.
Stainless bolts are NOT high tensile.
There's no such thing as "8.8 grade bolts". The metric designation is Class 8.8 and the imperial designation is Grade 8, but they
are not remotely comparable in strength.
If using metric fasteners, choose Class 10.9 for highly stressed applications and Grade 8 for imperial fasteners.
High tensile stainless fasteners are available in 17-4PH stainless, but why bother. The zinc or cadmium plated steel fasteners wont rust away in the
time you own the car.
With respect.
The material strength of a bolt is denoted on the top of the hexagon head. For high tensile metric bolts it is 8.8 (50 Tons per sq in) and 10.9 (65
Tons per sq in). Grade 12.9 (75 Tons per sq in) is also available but in Socket Cap screws only. For metric mild steel the grades are 4.6 (25 Tons per
sq in), 5.6 (28 Tons per sq in), and 6.8 (40 Tons per sq in).
For British bolts the grade for high tensile is the letter "R" (45 Tons per sq in), and for American it is the letter "S" (50
Tons per sq in). The latter two equate in strength to 8.8 grade in metric.
When a nut is used to tighten a bolt you must ensure that the grade is the same as for the bolt or higher. The strength is marked on the nut with a
single figure or letter. For example the figure "8" denotes a strength grade of 8.8.
By the way I do agree with the observations regarding suspension mounting bolts.
[Edited on 26-9-05 by BKLOCO]
Experience is what you get when you don't get what you want!!!
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