Is there anyone who does not use titleblock tolerances?
Is there anyone who does not use titleblock tolerances?
(OP)
I am trying not to overload other threads so I started this one for this, Do any of you really not use title block tolerances on your drawings? What type of industries/parts/assemblies are they?
I myself am in aerospace now: many sizes of fans, small air valves and actuators. Very small quantities that the big guys leave behind, not large quantities. Previously, I was in large specialty machines and transfer line machine tools mostly for the auto industry. Huge castings and weldments, all kinds of machined parts, and high precision machining parts, again small runs not likely to throw away after making a large investment. I believe this is one reason I have seen such bad fabrication tolerance practices, always has to be 2 place dimensions. What does it mean? ABSOLUTELY NOTHING!! Just a picture of what you want and you take what you get.
Frank
I myself am in aerospace now: many sizes of fans, small air valves and actuators. Very small quantities that the big guys leave behind, not large quantities. Previously, I was in large specialty machines and transfer line machine tools mostly for the auto industry. Huge castings and weldments, all kinds of machined parts, and high precision machining parts, again small runs not likely to throw away after making a large investment. I believe this is one reason I have seen such bad fabrication tolerance practices, always has to be 2 place dimensions. What does it mean? ABSOLUTELY NOTHING!! Just a picture of what you want and you take what you get.
Frank





RE: Is there anyone who does not use titleblock tolerances?
I guess that's still a title block tolerance, but not the plus/minus variety.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: Is there anyone who does not use titleblock tolerances?
All dwgs need tolerances on the face somewhere, in the block or with the dim.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Is there anyone who does not use titleblock tolerances?
The titleblock tolerances require you to show the trailing zeros of your dimensions. In ASME Y14.5, you are not to show trailing zeros on your metric drawings. I don't.
If it takes me more than two minutes to apply tolerances to each and every dimension on my drawings, it is because I discovered that my intended tolerance did not work, and I had to go back and modify the design. Tolerance stacks are a pain in the butt sometimes.
There is a lesson in there somewhere.
RE: Is there anyone who does not use titleblock tolerances?
Heck, if you're willing to right your own little disclaimer you could do trailing decimals on metric, it would be your variation from 14.5 which comes at the risk of causing confusion.
You could be really european and invoke iso2768 but I'd rather not thank you.
fsincox, I thought similar, or at least complaints about over reliance on block tols rather than calculating functional tols had been discussed before in detail.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Is there anyone who does not use titleblock tolerances?
My point will be erroneous tolerances are no better than none if you think about it, people become numbed by it.
j-p
I have been advocating that for about 15 years now. I want to combine the general profile to a master framework with an ISO tolerancing structure; unfortunately I need to work for ISO people first.
Frank
RE: Is there anyone who does not use titleblock tolerances?
"fsincox, The title block tolerances require you to show the trailing zeros of your dimensions. In ASME Y14.5, you are not to show trailing zeros on your metric drawings. I don't."
Sorry I don't get your point here. I detest the practice of tying tolerance expression to the number of decimal places I feel it is too easily abused.
Frank
RE: Is there anyone who does not use titleblock tolerances?
If no tolerance shown with the dim, use a tol block.
Show no tol or tol block, do not expect good results from finished parts.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Is there anyone who does not use titleblock tolerances?
Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services
www.infotechpr.net
RE: Is there anyone who does not use titleblock tolerances?
What you stated is what I realised when I was first trying to get my mind around the ISO system, years ago. I suddenly realised that in the end it is only because of our "inbreeding" that we think of decimal places as implying tolerance ai all. What exactly do you mean or can you expand on "historically"? Do you know thw history of how this came about?
People claim they care about these issues. I have seen all my life companies take jobs from ISO companhies and not even bother have a copy of them or to understand their standards.
Frank
RE: Is there anyone who does not use titleblock tolerances?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Is there anyone who does not use titleblock tolerances?
Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services
www.infotechpr.net
RE: Is there anyone who does not use titleblock tolerances?
I had not got to those threads yet I am starting from the back (pg 54)and only about to pg 50. Those are good ones. That is why I decided to read through the posts here, I finally learned how to use archive too, Is there a limit to the archive?
Frank
RE: Is there anyone who does not use titleblock tolerances?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Is there anyone who does not use titleblock tolerances?
That is sort of what I was saying. Setting the decimal places of your dimensions is really not much more convenient than thinking about and setting the tolerances individually. The tolerance block ought to have and usually has a statement like "UNLESS OTHERSISE SPECIFIED", so you can do anything you want.
I am annoyed and frustrated at people who, obviously, have populated the drawing with three decimal English, or two decimal metric dimensions, and are satisifed that they have toleranced everything. This sort of works in a machine shop, but is completely disfunctional for welders.
RE: Is there anyone who does not use titleblock tolerances?
RE: Is there anyone who does not use titleblock tolerances?
Anything that has to be closely controlled get an explicit tolerance and probably a critical characteristic symbol too.
RE: Is there anyone who does not use titleblock tolerances?
But with that said the vast majority of companies still have them and I don't see them going away.
With CAD it is very easy to add a tolerances to individual dimensions, and I prefer that - with some exception.
RE: Is there anyone who does not use titleblock tolerances?
I would be VERY interested to know how you have come to that conclusion. If the drawings reference something like: ISO 2768-mH (or similar) it is all in there. They just don't do it like we do.
Frank
RE: Is there anyone who does not use titleblock tolerances?
RE: Is there anyone who does not use titleblock tolerances?
Frank