stainless steel nuts and bolts

May 24, 2012 14 Replies

Hi,



Looking at Tool station prices, BZP nuts and bolts are much cheaper than the stainless steel versions. The stainless steel is approximately four times more than the BZP. So why is it that SS washers cost about the same as BZP washers? Why is there not the same



4x differential? Is it that less machining is involved to manufacture them?

Is there any reason to buy BZP washers when you can have SS for the same price?



TIA


Probably because washers are stamped but nuts and bolts machined. Stainless is a bit more difficult to machine than mild steel.

BZP washers require more manufacturing operations than SS. they both need stamping and then the stainless is finished. The BZP then need cleaning, plating, cleaning, etc.

Stainless screws need different manufacturing to BZP.

I thought most bolts and screws were rolled???

Horse's bolt, people get screwed and joints are rolled ;-) simples

You owe me a lid then.

I thought I'd had some machined stainless bolts or studding a while ago but, quite right, my latest M8s are rolled. The nuts are tapped, though.

Though you might well find they're using fluteless taps which just displace the metal rather than cutting it - so similar in principle to rolled threads...

In most circumstances I don't see a problem with that. Sometimes stainless can become embrittled, but that's referring to studs and bolts.

Thanks. That seems obvious now but I hadn't thought of that before. This may be another daft question but BZP is bright zinc plated. Why "bright"? Is there a dull zinc too? TIA

passivated. I cant recall what with, but I think its zinc chromate - yellowish greenish layer that you see on a lot of steel kit.

Well, they *look* tapped to me, under a magnifying glass. And I am a tribologist.

They can't touch you for it.

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