Plans & Designs - Symbols?

[JimM]

Hi all

Has anyone got any good links to sites that explain what the various symbols used on engineering plans and designs mean.

Specifically, I've got a couple of the 'Workshop Practice' books and on turned and bored parts they often have 2 symbols on the plan....

The first is 2 circles, one inside of the other
The second is what looks like a small bung or cork (like those use to plug test tubes)

I'm guessing one of the symbols means that the bore should be concentric but after that I'm stuck.

Any pointers much appreciated

Cheers

Jim

 

[vlmarshall]

That's the Projection Angle symbol. It shows you which way parts are flipped on a three-view drawing.
Basically, parts are either "tumbled" or "scooted" around on the page... I'd say that "Third Angle", or what I called "Scooted" is the more common. ;D

 

[Maryak]

Jim,

An explanation of the difference between the two.

Hope it helps. ???

Best Regards
Bob