how to read hole tolerance

[dogbural]

Hi,

I have this supplier drawing.

In tolerance specification, it says hole +/- 1.
Does this indicate hole diameter size +/- 1mm or distance between two holes?

Regards,

 

[3DDave]

Seems ambiguous. Ask the supplier. It could be hole spacing tolerance or hole diameter tolerance or, least likely, hole depth tolerance. At the worst it means if the drawing calls for 10 holes you will get 9, 10, or 11 holes.

 

[Wuzhee]

I love these, as I was a former perpetrator of such horrors. I thought if I slap some general tolerance blocks the suppliers would enjoy a lot of freedom and I don't have to discuss everything in detail because the loose title block values could provide us good parts and lower cost without much hassle.
Contrary to popular belief, these title block tolerances are the worst enemies of manufacturing (except Caterham maybe) firms, and they are only good to confuse, distract and enrage people.