Stainless Steel Screws.

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landsurfer
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Location: Rotherham

Stainless Steel Screws.

Postby landsurfer » 1 Sep 2019, 4:49pm

The picture shows the screws holding the handlebars on to my bike. They have been fitted for just over a year and although sold as Stainless Steel you can see the corrosion.
I suspect they are S316 stainless .. so, barely stainless, magnetic and prone to corrosion.
Does anyone know a source of M5 and M4 screws that are of a higher grade of stainless ?????

V3dgHx5PQtu+Bulq%OcEwg.jpg
It's just like that, it's just the way it is.
The road goes on forever.

reohn2
Posts: 36417
Joined: 26 Jun 2009, 8:21pm

Re: Stainless Steel Screws.

Postby reohn2 » 1 Sep 2019, 5:02pm

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PH
Posts: 7604
Joined: 21 Jan 2007, 12:31am
Location: Derby
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Re: Stainless Steel Screws.

Postby PH » 1 Sep 2019, 5:03pm

I used to use a local fixings and ironmongers shop, but they introduced a minimum charge, so have been using Ebay, I'm sure any of them with good feedback would be OK, my last couple of purcheses have been from bolt-world and I've been buying A4 stainless screws
https://www.ebay.co.uk/str/Bolt-World/S ... 3848538010

reohn2
Posts: 36417
Joined: 26 Jun 2009, 8:21pm

Re: Stainless Steel Screws.

Postby reohn2 » 1 Sep 2019, 5:11pm

PH wrote:I used to use a local fixings and ironmongers shop, but they introduced a minimum charge, so have been using Ebay, I'm sure any of them with good feedback would be OK, my last couple of purcheses have been from bolt-world and I've been buying A4 stainless screws
https://www.ebay.co.uk/str/Bolt-World/S ... 3848538010

I've used Boltworld in the past on Ebay decent company to deal with IME
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I cycle therefore I am.

alexnharvey
Posts: 812
Joined: 10 Jan 2014, 8:39am

Re: Stainless Steel Screws.

Postby alexnharvey » 1 Sep 2019, 6:02pm

Check the bolt size carefully, stem bolts are sometimes m7 which I think you will have to order from a specialist bike supplier.

Eyebrox
Posts: 253
Joined: 5 Aug 2015, 8:56pm
Location: Ayrshire

Re: Stainless Steel Screws.

Postby Eyebrox » 1 Sep 2019, 6:49pm

I fill the hex bolt heads with clear grease to prevent rust. It's worked fine over many years.

WOT
Posts: 7
Joined: 22 Aug 2019, 9:43pm

Re: Stainless Steel Screws.

Postby WOT » 1 Sep 2019, 6:56pm

A4 and 316 are pretty much equivalent grades. Given that the corrosion is only internal it may well be transferred material from the Allen Key used to tighten them, rather than the screw material.

We use this vendor for A4 / 316 screws of various lengths and sizes.

http://www.inox.ie/acatalog/Cap_Screws.html

landsurfer
Posts: 4998
Joined: 27 Oct 2012, 9:13pm
Location: Rotherham

Re: Stainless Steel Screws.

Postby landsurfer » 1 Sep 2019, 7:08pm

It is structural corrosion, not transfer.
Iron oxide that often occurs with S316 and A4 structures.The screws could well be plated iron.
I have recently removed part of a traction control system from a major UK train fleet that was specified in Stainless Steel.
The label on the cylinder was made of stainless steel !!!
The cylinder was plated iron ... we only found out when the metal recycler did some test drillings to ascertain the material grade.
As a professional Aerospace Engineer corrosion has been part of my working life, now in the Rail industry i see loose specs for S316 appearing all the time.
It corrodes.
It's just like that, it's just the way it is.
The road goes on forever.

User avatar
ConRAD
Posts: 638
Joined: 20 May 2010, 10:55am

Re: Stainless Steel Screws.

Postby ConRAD » 1 Sep 2019, 7:59pm

landsurfer wrote:... and although sold as Stainless Steel ... I suspect they are S316 stainless ...

316SS, or better AISI316, is definitely a good and very popular stainless steel.
AISI316 is definitely stainless and totally amagnetic ... so test your bolts with a magnet, if you note some attraction ... then those bolts are nor 316.
Image

rmurphy195
Posts: 1428
Joined: 20 May 2011, 11:23am
Location: South Birmingham

Re: Stainless Steel Screws.

Postby rmurphy195 » 1 Sep 2019, 11:58pm

I've had loads of stuff from Namrick, here is theier stainless products
https://www.namrick.co.uk/acatalog/Home_Metric_Stainless_Steel__Grade_A2_and_A4__54.html
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
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Brucey
Posts: 35987
Joined: 4 Jan 2012, 6:25pm

Re: Stainless Steel Screws.

Postby Brucey » 2 Sep 2019, 12:12am

landsurfer wrote:The picture shows the screws holding the handlebars on to my bike. They have been fitted for just over a year and although sold as Stainless Steel you can see the corrosion.
I suspect they are S316 stainless .. so, barely stainless, magnetic and prone to corrosion.
Does anyone know a source of M5 and M4 screws that are of a higher grade of stainless ?????

V3dgHx5PQtu+Bulq%OcEwg.jpg


those are not stainless steel bolts. Therefore any stainless steel bolt would be 'a higher grade of stainless' than those.


The two most common stainless bolt grades are A2 and A4 which roughly correspond with AISI 304 and AISI 316 stainless. A2 contains a small amount of ferrite and is weakly (about 1/10 as much as with a similar 8.8 bolt) arracted to a magnet; it is also stronger and slightly less corrosion resistant than A4. Typically AISI 316 stainless contains between zero and about 5% ferrite and is even less attracted to a magnet.

You can use A4 grade bolts in an a marine environment and they struggle to manifest any visible corrosion. A4 bolts can be made to corrode badly but if the bolts in your picture are A4 bolts and have gone like that then conditions are so severe that there would be practically nothing left of the bike they are attached to.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

nez
Posts: 1637
Joined: 19 Jun 2008, 12:11am

Re: Stainless Steel Screws.

Postby nez » 2 Sep 2019, 6:11pm

I have replaced bolts like these with titanium. They're a bit expensive but for definitely no rust applications I love them. Pedal axles, odd nuts and bolts.

fastpedaller
Posts: 2122
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Stainless Steel Screws.

Postby fastpedaller » 2 Sep 2019, 7:01pm

A friend once quoted "stainless means one stain less than mild steel :lol: "
I've found the stainless set screws/capheads/domeheads sold by Screwfix to be of good quality.

Brucey
Posts: 35987
Joined: 4 Jan 2012, 6:25pm

Re: Stainless Steel Screws.

Postby Brucey » 2 Sep 2019, 8:27pm

fastpedaller wrote:A friend once quoted "stainless means one stain less than mild steel :lol: "
I've found the stainless set screws/capheads/domeheads sold by Screwfix to be of good quality.


choice of A2 and A4 grades from Screwfix

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Samuel D
Posts: 2883
Joined: 8 Mar 2015, 11:05pm
Location: Paris

Re: Stainless Steel Screws.

Postby Samuel D » 2 Sep 2019, 8:50pm

I have used Westfield Fasteners on the recommendation of 531colin of this forum and was pleased with the the whole transaction. Works well for small orders. Plenty of metric bolts.