Tolerance Blocks on drawings

[John Kingston]

We are having some discussions here regarding tolerance blocks and the correct usage of them. We have our "standard" tolerance block. Any dimensions that require a different tolerance are shown with a tolerance on the print. When we receive a customer print with a tolerance block different than ours, a note is added to the drawing that shows the customers tolerance block. Here is the problem, no flag is placed near the tolerance block on our print. I've seen a number of manufacturing personnel stop looking once they see the "standard" tolerance block. I feel this is poor practice by Engineering/Drafting. I'd like to hear everyone else's thoughts.

[Jeffrey Lovely]

and then they will build a gage that dont match either tol group !!!

[kbotta]

I don't think you should have 2 tol. blks on a single drawing. Personal pref.
I'm not sure, but I think the line convention group (asme) might have a standard for that, but don't quote me.
It would seem you would want a simpler drawing, not a more complicated one. Why can't you omit yours when the customers goes on, and visa versa??
i wouldn't like that.

What about crossing (X) one out???
I've seen JIS and DIN and ISO and ASME done this way...
Kev

[ag162]

I feel that if there is a deviation to the general tolerance, then it nefinately needs a flag or a note. All personel involved needs to be able to read a print and that includes paying attention to the details of the print.

A.Gore

[Paul Sarrach]

I see where that could get confusing. I see where some may take advantage and go with the biggest tolerance or that conforms with there need. I personlly would not have two blocks. But in the end I would have to say whose is the end user, and use there block.

[T Miller]

I'm a bit lost... the customers print has the block on it.. how did your company get there block on the dwg to..

[Perry Fisher]

I'm guessing at an answer to Tom's question because I'm working on PPAP's at this time with prints in which our customr has pasted their customer's prints onto their own title blocks.

In this case I only have 1 tol block but can easily see a scenario that would have 2 tol blocks. If I were to see prints with 2 tol blocks I would not accept them from our eEng Dept until one of them was removed or crossed out.

[Aguayo]

Well some drawings have the tolerance block for the dimensions shown on the drawing and then they will have another tolerance block for features or dimensions that are not dimensioned or specified .

[John Kingston]

We create our own drawing. So it isn't really 2 tolerance blocks, but our tolerance block, and then a note with tolerances in it.

IE Note 5. Tolerances UOS
.XXX +/-.010
.XX +/-.030

So which UOS applies? It can put you in a loop, cause the drawing tol block also says UOS.

[rebeldude]

I would guess any dimensioned areas marked with a 5 will have those particular tolerances you are showing us applied, and any not marked with a 5 would default to the other tolerance block. Thats how I would personally read it

[John Kingston]

I would guess any dimensioned areas marked with a 5 will have those particular tolerances you are showing us applied, and any not marked with a 5 would default to the other tolerance block. Thats how I would personally read it

Yes, but they aren't flagging any dimensions. Just a note with a different tolerance block. Hence my frustration. Really ticks of the setup guys when I have to show them their part is out of tolerance because they looked at the drawing they way they have for 20 years!

[rebeldude]

John,
It seems to me that I spend all day long ticking people off! But if nothing is flagged, then so be it right? Unless the print is updated, or if they sign something stating otherwise, then you got to go by what imformation is handed to you.

[John Kingston]

I'm in the same boat. Tick 30 people off by doing the job right. Tick off my boss, his boss and myself by bending to their whims. In the end I report to the QC Manager, President of the company, Customers, and Myself. QC is a thankless job at times, but I love and live it.

[rebeldude]

LOL. You got that right!

[kbotta]

Yeah, it's nice to be able to sleep good at night knowing you did your best...And not having to sit there in a pool of sweat with a 40 ounce and a loaded shotgun - hoping to pass out...