C21 Thread

[Col Mckee]

So...What is a C21 Thread? No guessing, please!

[mochinist]

Never heard of it, what is it on, or what does it go to?

[CCWKen]

I think they use "C" series to designate light bulb thread. I have no idea what the specs are.

[Col Mckee]

Drill rod

[DR]

Huh????

[Col Mckee]

Drill rod; as in oil fields

[wierdscience]

Like so-
http://www.diedrichdrill.com/specs/rodsp.htm

I got a API standard thread casing chart,but nothing on drill pipe,or couplings.

[Paul Alciatore]

Some Hits:

http://www.mttusa.net/id448.htm

http://www.n-ccarpet.com/Serging_yarn_order_form.htm

http://www.fostercomfg.com/Catalog/Couplers%20Plugs.pdf

I have several catalogs on lamps. I can not find any threaded lamp bases described as C21 or any other style that starts with the letter "C". There is a C21 that is a pin style socket, perhaps for fluorescents. It has no threads.

Paul A.