Engineering Drawing Symbols

[ebjacob]

Some of the drawings have the symbols as attached.I would be grateful, if anybody can help me understand what actually the symbol define?
its like a corner showing + symbol and - sybmol with tolerance.

 

[btrueblood]

It's a tolerance for a sharp corner, i.e. the corner can be chamfered/radiused up to the limit shown. Believe it's an ISO symbol, not an ANSI symbol.

see

http://www.practicalmachinist.com/vb/general/chamfer-vs-edge-condition-drawings-iso-333845/