What kind of plating is this?

Yellow cad?

I wondered if it was cadmium myself. But I thought cadmium was poisonous. Is it still used? I've recently seen the same colour plating on brand new items.

Best wishes,

Chris

Think I just answered my own question. Here's a good article on the subject:

Best wishes,

Chris

The irridite finish can also be applied to zinc plating as I recall. Cadmium has fallen out of favor, although it is likely still used for defense purposes.

Harold

Can somebody explain this bolt, which is from the above link about coatings?

Those look *like* threads but I don't think they *are* threads.

Dave

I read a lot of requirements specifications these days and Cadmium is on the prohibited materials list. But you can get permission to use just about anything if you convince the procurement office it is in the best interest of the military.

Carl Boyd

Phosphate coatings often are yellow, and they can be (and often are) applied on top of plating.

-- Ed Huntress

Those look *like* threads but I don't think they *are* threads.

They are threads, but I'd guess they're not of any practical use. At a glance, I would say it's a cylinder head stretch bolt, and the 'threads' are possibly added to modify the stretch properties of the bolt.

Here are a couple more interesting links I found:

Right. Zinc plating affords good rust protection, but it is very vulnerable to even mild acids like fingerprints and acid rain. A dunk in the chromate give the zinc better resistance to mild acids.