Re: stainless steel bolts

On 11/7/2024 6:27 PM, Paul in Houston TX wrote:

Colour Sergeant Bourne wrote:

On 11/6/24 5:49 PM, Paul in Houston TX wrote:

Larry Wolff wrote:

How can I tell if these bolts are stainless steel or not?
https://i.postimg.cc/8cMgwY4Y/bolts.jpg
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All I know is they're heavy feeling - and magnetic.
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But how do I know if they're stainless short of purposefully rusting them
by dipping them in acid?

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If the pic is of the actual bolts...
The bolts do not look like stainless - they look like low quality steel bolts plated with zinc.  The manufacturing looks poor.
IMO, they are the 13 cent variety, not the $1.13 variety.  Same for the nuts. They are the 5 cent variety, not the 55 cent variety.
There is low quality stainless but I have never seen that used in nuts and bolts.  Threaded pieces are normally 18-8 or better and have better machining.

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Whar are the tip-offs in the picture that they ared ow quality?

 It's difficult to say for sure with out viewing the head markings or seeing better photos.  It could be the small pixel count of the photo or the zinc plating, but... the machining just does not look crisp / sharp.    There are striations on the bolt head and nut that are not seen on quality bolts and nuts.  The nut appears to be much thinner than a good quality nut.
 

You're right, it's difficult to say with certainty.
There are chemical and spark tests which I linked in a reply the other day which are much better than images.
Here are M5 ULS stainless we sell in a parts packet:
http://www.yellowjersey.org/cleat18d.jpg
Typical SNP steel ULS:
https://helmi-sport.de/en/p/uls-screws-m6x20
https://images-na.ssl-images-amazon.com/images/I/51jJbwulu5L._SL1201_.jpg
depending on the camera and lighting they look pretty much similar.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971