I have boxes of stainless screws from 3/8 ' to 3' of varying diameter, mainly flat head, but a few pan head, 1000 pieces to a box  I buy them at the local lumber supply store in the small town near my home.  I never had a problem getting the length that I needed but sometimes the diameter and type of head.

You can buy less than a whole box but have to wait while someone counts them.  They sell them buy the piece

 

They count  bolts, nuts and washers and then weigh them because they sell them by weight.

 

Rope and chain are measured and then weighed as it's also sold buy weight.  If you ask how much does a meter cost they respond with the price per kilogram.

1 hour ago, flyingfox1 said:

Went into
Mega home ransit of coarse!!! Thanks for reminding me I will look down there today

They will of course be out of every size you need, stock control is not one of their fortés.

 

Just a reminder; the OP asked for marine grade stainless, not 304.

 

Anyway, even 316 needs care.

I have quite a few panels made of 316, most of them polished to mirror finish quality, they last for years

without any care.

Now and then I experience som rust spots on 316 nuts and bolts.

I have some moulded 316 pipe fittings (not polished) these get rust spots.

Maybe coating is a good idea, if they are not opened and fastened routinely.

(maybe powder colouring?)

 

As to distinguishing 304 from 316:

There are small bottles of test liquids you can buy for checking 304 versus 316.

 

If you have a small piece of 316 and a small piece of 304 you put a couple of drops on each piece,

after abouy 5+ minutes the 304 will look same same whilts the 316 will take on an ugly yellow/brown colour.

 

Selling price is 175 baht for 500 of the self tapping screws in Buriram. It might be less at a store closer to Bangkok. #8 2" flat head phillips. 

45 minutes ago, David B in Thailand said:

Selling price is 175 baht for 500 of the self tapping screws in Buriram. It might be less at a store closer to Bangkok. #8 2" flat head phillips. 

Ok

But what kind of metal are they made of?

I found a M8x40mm stainless machine screw at this place. They had tons of others also. Do a google map search for: บริษัท น็อต แอนด์ สกรู จำกัด

 

 

zombie post, but lazada got 'em.

 

Self Tapping Screw #7x2" (Pack 50)

฿65.00

 

https://www.lazada.co.th/products/titan-7x2-fh-pack-50-i221038187-s337190072.html

 

and

 

https://www.lazada.co.th/products/meta-30-x-2-100-i113959540-s117838743.html

On 5/14/2018 at 1:02 PM, ChouDoufu said:

zombie post, but lazada got 'em.

 

Self Tapping Screw #7x2" (Pack 50)

฿65.00

 

https://www.lazada.co.th/products/titan-7x2-fh-pack-50-i221038187-s337190072.html

 

and

 

https://www.lazada.co.th/products/meta-30-x-2-100-i113959540-s117838743.html

They are not marine grade stainless, probably not stainless either as SS isn't usually hard enough to be self tapping.