Stainless Steel

DWS · Post by **DWS** » Mon Dec 20, 2010 9:08 am

I've just purchased some stainless steel fittings for my Matchless from a 'specialist' supplier but I'm not happy with the finish. I'm no expert on stainless but the surface of the items seem to be corroded? One of the items is shown below. In the past, stainless steel items I bought (mainly for older BMWs) were always nicely finished and mark free, anyone know what's going on here? Poor grade stainless maybe?

GSAX1 · Post by **GSAX1** » Mon Dec 20, 2010 9:18 am

I have seen this before. I don't think it is corrosion but just rough finishing.

By the way, here is an interesting tech. article that indicates why stainless steel should not be used with aluminium.

https://www.jampot.com/article_read.asp?id=536

Michael

Eric · Post by **Eric** » Mon Dec 20, 2010 10:31 am

It looks like a hexagon section that was drawn whilst red hot and cleaned up afterwards, rather than cold drawn to finish it that would leave a clean bright surface.

Or a section that was originally a hot drawn one that was intended for later finish sizing by cold drawing, but was not really large enough to clean up properly at final size.

I guess it all depends upon how much you paid for it, its certainly not the standard I would expect for Bright Drawn Stainless Steel.

alanengineer · Post by **alanengineer** » Mon Dec 20, 2010 11:45 am

I have had a lot of this quality finish lately and from various suppliers. Its something we are going to have to get used to. If it were for a position that will be seen and critisized, the huge cost of machining a hex might be considered or just 'potluck' on the material supplied.
I keep a lot more (in proportion to its need in the workshop) stainless steel in stock for this very reason.
You could just rub it down the linisher to smarten it up a bit

DWS · Post by **DWS** » Mon Dec 20, 2010 1:05 pm

Hi Alan, I hear what your saying about Stock Hex Bar that is ordered by someone making parts however, when I order stainless steel parts and fittings for my Matchless from a "Specialist supplier of stainless steel parts for Matchless & AJS motorcycles" I don't expect to have to finish the parts off myself, especially when the photos of the parts on their website shows nicely finished off items. The part shown in the photo is not a piece of stock hex bar, it is in fact the large nut that fits onto the the right hand end of the dynamo strap mounting. You may have answered my question though, it seems the items were just not finished off correctly? Here is another photo of a stud and nut supplied.

GSAX1 · Post by **GSAX1** » Mon Dec 20, 2010 1:47 pm

To obtain the correct 'Cadmium plated' look you should bead blast the nut/bolt. Then the pitting will not be so apparent.

Michael

Eric · Post by **Eric** » Mon Dec 20, 2010 3:32 pm

The part shown in your 1st photo was made from hex bar, the same as the nut in your second picture.

Its really just poor quality hex bar. Perhaps the only way to get things improved is tell your supplier the quality is not what you expect and ask for a price reduction or return the parts and ask for a re-fund.

In turn your supplier will do the same with his supplier untill it gets back to source and they improve the quality.

At the moment they seem to be saying anything is acceptable that will just have to do.

DWS · Post by **DWS** » Mon Dec 20, 2010 5:29 pm

I am still waiting for a reply from my supplier...

alanengineer · Post by **alanengineer** » Mon Dec 20, 2010 7:35 pm

if you dont buy much stainless steel, you dont get much of a choice. if you do buy a lot, you dont get much either.
All raw materials are getting more and more difficult to source. And then you have to pay through the nose for it

alanengineer · Post by **alanengineer** » Mon Dec 20, 2010 7:37 pm

In addition to above. i have never been offered round stock that has such a poor surface finish. The hex, yes.