Stainless steel bolts

[bsa250]

Hi Folks,
Can anyone let me know what grade Stainless steel can be used

to secure front disc calipers etc, what I'm after is to take out a few rusty bolts

here and there and replace with SS but there are different grades of SS

for custom and strengh 316 grade springs to mind can anyone back that up ?


Best regards Mack....

 

[thornley]

Don't use A2 on brake parts. Best just clean up existing bolts on brake parts, 316 grades will work harden due to chrome and nickel content. A2 is fine for cosmetics such as engine casings and the like

 

[motobiker]

For something like this I would suggest you get in touch with Steptoe - he includes S/S disc bolts in his kits. Ahnd I'm sure I read in one of his posts that there were absolutely no problems reported despite 100's of sets sold. He may be able to supply these as a stand alone order - or if not will tell you whats what and where to go. (or get off)

btw - if I was doing this (or rather when - in my case its pencilled in for the happy day the discs are replaced.) I will replace all the bolts

Hope that helps.

 

[thornley]

For something like this I would suggest you get in touch with Steptoe - he includes S/S disc bolts in his kits. Ahnd I'm sure I read in one of his posts that there were absolutely no problems reported despite 100's of sets sold. He may be able to supply these as a stand alone order - or if not will tell you whats what and where to go. (or get off)

btw - if I was doing this (or rather when - in my case its pencilled in for the happy day the discs are replaced.) I will replace all the bolts

Hope that helps.

He'll be along shortly

 

[Supertech]

A2 or a4 perfectly ok on discs. I use 303 as well that machines nicely.

 

[bsa250]

SS Bolts

Hi Folks,

Thanks to one and all for your info, I can now decide what to get

in SS for the Calipers.

Best regards Mack.....

 

[alimey4u2]

I hope Supertech has liability insurance....

 

[Welshman]

All I know is, do not use A4 on your shocker.... they shear

I rode 200miles home with an Allen key in there which got me back...

 

[Supertech]

I hope Supertech has liability insurance....

Me and just about every other fastner supplier, try finding kits that have different grades of stainless. If the bolts are special ones that have been machined I'll have a fiver on the fact they will have been made from from 303 or similiar.


Bad luck on the rear suspension bolt, why did it fail? Is the standard bolt a close tolerence jobby? If so sticking a normal bolt in is likely to be a problem - no matter what material you use. I've used stainless for years and never had any problems and the grades I chose are the same ones now universally used in all replacement bolt kits.

 

[Welshman]

Me and just about every other fastner supplier, try finding kits that have different grades of stainless. If the bolts are special ones that have been machined I'll have a fiver on the fact they will have been made from from 303 or similiar.


Bad luck on the rear suspension bolt, why did it fail? Is the standard bolt a close tolerence jobby? If so sticking a normal bolt in is likely to be a problem - no matter what material you use. I've used stainless for years and never had any problems and the grades I chose are the same ones now universally used in all replacement bolt kits.

No its just that the standard is a 12.9 or similar, the A4 just does not have that shear strength, plus we ride rough terrain...

 

[thornley]

I have never posted qualifications on here but I am a Chartered Mechanical engineer. Honours degree and ex production manager for the then world's largest producer of Superalloys for aerospace and chemical plant applications.( Haynes international).Stainless steel A2 should not be used in high stress applications. It should never be used on brake parts,suspension parts full stop. It does not have the necessary strength, nickel work hardens, brakes do a lot of work. Bolts will fail if subject to the original design limits.

A2 is generally supplied chemistry only, it is generally not a traceable and tested material (mechanical properties), it is not designed for high stress application.

Looks good but A2 (316, 316L, 303, etc) is suitable only for cosmetic applications. I'm not surprised the shock bolt failed, as quite rightly pointed out some riders give the GS the stick it was designed for. The original bolts are not just picked out of a parts bin. Engineers choose materials for application, not because they are nice and shiny.

My views would stand up in court

By all means fit bolts as you choose, never offer me a pillion ride.

 

[Slowdown]

.....Stainless steel A2 should not be used in high stress applications. It should never be used on brake parts,suspension parts full stop. It does not have the necessary strength, nickel work hardens, brakes do a lot of work. Bolts will fail if subject to the original design limits.
....

....so is there anything that's stainless that you could use to hold the disks on? ProBolt sell A4 grade bolts and they've not been sued (yet?)

 

[Welshman]

I have never posted qualifications on here but I am a Chartered Mechanical engineer. Honours degree and ex production manager for the then world's largest producer of Superalloys for aerospace and chemical plant applications.( Haynes international).Stainless steel A2 should not be used in high stress applications. It should never be used on brake parts,suspension parts full stop. It does not have the necessary strength, nickel work hardens, brakes do a lot of work. Bolts will fail if subject to the original design limits.

A2 is generally supplied chemistry only, it is generally not a traceable and tested material (mechanical properties), it is not designed for high stress application.

Looks good but A2 (316, 316L, 303, etc) is suitable only for cosmetic applications. I'm not surprised the shock bolt failed, as quite rightly pointed out some riders give the GS the stick it was designed for. The original bolts are not just picked out of a parts bin. Engineers choose materials for application, not because they are nice and shiny.

My views would stand up in court

By all means fit bolts as you choose, never offer me a pillion ride.

The worst thing is I,m an Engineer....

 

[thornley]

....so is there anything that's stainless that you could use to hold the disks on? ProBolt sell A4 grade bolts and they've not been sued (yet?)

A4 is suitable for some brake disc applications. It depends on how over engineered the original fixing is. i.e how many bolts, diameter, form etc. Fasteners are selected not just by grade but by application. It's quite possible that the original bolts are 100% over engineered and so a material with 20% less overal tensile/shear/impact strength is acceptable.

Stainless steel is so generic a term as to be meaningless. It is dependent on actual chemistry ( nickel/chrome content any other alloys, contamination in the melt) quality control, method of production, final heat treatment, testing requirements i.e does it come with mechanical testing certification detailing actual batch properties. The engineers who select critical part fasteners do so based on over engineering, they don't want to be sued. With the exception of some very expensive alloys stainless steel grade will not out perform OEM bolts and in the worst case are useful for the catering industry holding together pots and pans.

I personally would not fit any stainless grade to brake or suspension/critical frame parts. I know the chances of a failure are low BUT if a disc sheds its bolts you are in for an oh sh*t moment and if an accident investigator found that critical parts had been replaced with lower grade materials you can kiss the insurance goodbye.

You pays your money you makes your choice.

 

[Steptoe]

I never use stainless on shock absorber bolts/mounts.

They aren't supplied in my stainless kits.

 

[thornley]

I never use stainless on shock absorber bolts/mounts.

They aren't supplied in my stainless kits.

We had a discussion some 4 years ago on this and it's apparent you know your stuff and are a responsible supplier. Unfortunately as you know not all suppliers know the technical requirements as well as you do. I have seen custom bikes held together with bolts that would not be suitable on a kids trike. I would always pass any BMW related enquiry your way.

Ps no ar*e licking, simple respect.

 

[alimey4u2]

I have never posted qualifications on here but I am a Chartered Mechanical engineer. Honours degree and ex production manager for the then world's largest producer of Superalloys for aerospace and chemical plant applications.( Haynes international).Stainless steel A2 should not be used in high stress applications. It should never be used on brake parts,suspension parts full stop. It does not have the necessary strength, nickel work hardens, brakes do a lot of work. Bolts will fail if subject to the original design limits.

A2 is generally supplied chemistry only, it is generally not a traceable and tested material (mechanical properties), it is not designed for high stress application.

Looks good but A2 (316, 316L, 303, etc) is suitable only for cosmetic applications. I'm not surprised the shock bolt failed, as quite rightly pointed out some riders give the GS the stick it was designed for. The original bolts are not just picked out of a parts bin. Engineers choose materials for application, not because they are nice and shiny.

My views would stand up in court

By all means fit bolts as you choose, never offer me a pillion ride.

"Me" "Moi" "Yo" am in total agreement.... I would never use stainless steel ( of any grade) for this duty. Call me old fashioned ....

 

[Welshman]

I have never posted qualifications on here but I am a Chartered Mechanical engineer. Honours degree and ex production manager for the then world's largest producer of Superalloys for aerospace and chemical plant applications.( Haynes international).Stainless steel A2 should not be used in high stress applications. It should never be used on brake parts,suspension parts full stop. It does not have the necessary strength, nickel work hardens, brakes do a lot of work. Bolts will fail if subject to the original design limits.

A2 is generally supplied chemistry only, it is generally not a traceable and tested material (mechanical properties), it is not designed for high stress application.

Looks good but A2 (316, 316L, 303, etc) is suitable only for cosmetic applications. I'm not surprised the shock bolt failed, as quite rightly pointed out some riders give the GS the stick it was designed for. The original bolts are not just picked out of a parts bin. Engineers choose materials for application, not because they are nice and shiny.

My views would stand up in court

By all means fit bolts as you choose, never offer me a pillion ride.

No issues, I will advise if you want what my background is, but interesting little tube mills around Hereford used to supply me tons of inconel for refiinery duty.....