Tolerances for assemblys containing piping, welded and bolted constructions.

[Matt85]

HI,

I am working with alot of assemblys that contains piping, welded and bolted constructions. I would say that the drawings I do is mechcanical drawings, normaly I would say that they almost always has been drawn in iso 2768.
But if you start look at these things individulay like welded constructions and machined components and piping I am unsecure if this is correct. I mean it is harder to get the dimensions correct for welded constuctions then doing holes by a CNC machine.

What i have found there is different tolreces for this, see below:
Piping have thier own tolerances accrording to ss-en 13480.
Welded Construction tolerances iso 13920.
Mechined/bolted contructions tolerances iso 2768.

So my questions is how do you guys do on your drawings?
Is iso 13920 more for welded constructions for e.g the buidling industry?
If you have an assembly drawing that contains piping and a welded frame what wóuld be the tolerances ststed for that drawing?


//Matt

 

[MintJulep]

What can you get away with and still have your assemblies work as required?

 

[racookpe1978]

How expensive can you afford to be?

Loose tolerances are MUCH less expensive, often much faster.
However! Tight tolerances that make guess work and future equipment swaps and down-the-line assembly-work more standardized can - often do! - save money in the long run.

 

[Matt85]

For the assemblies I do, the tolerances is not that important,so that is why I want to change from iso 2768 to iso 13920, but is that common to do so on mechanical drawings?

 

[pylfrm]

Matt85,

Do you mean that conformance with the tolerances is not very important? If so, perhaps you should consider making them large enough that it is important.


pylfrm