SI units tol
SI units tol
(OP)
How do you read these tolerances?
Not sure how to add this symbol here, but "<_" is "less than or equal to".
x<_10, +/-0.1
10<x<_100, +/-0.15
100<x<_500, +/-0.25
500<x, +/-0.5
If a dimension is 165 or 22.5, what tolerance is used?
I have never used this type before.
Thanks.
Not sure how to add this symbol here, but "<_" is "less than or equal to".
x<_10, +/-0.1
10<x<_100, +/-0.15
100<x<_500, +/-0.25
500<x, +/-0.5
If a dimension is 165 or 22.5, what tolerance is used?
I have never used this type before.
Thanks.
Chris
SolidWorks 10 SP5.0
ctopher's home
SolidWorks Legion





RE: SI units tol
Its based on assumption that for certain manufacturing methods accuracy of dimension becomes smaller (tolerance is wider) as the nominal size gets bigger.
If the dimension is 165 the limits are 164.75 - 165.25.
If the dimesnion is 22 the limits are 21.85 - 22.15.
RE: SI units tol
Seems odd to me, but I understand it.
Thank you!
Chris
SolidWorks 10 SP5.0
ctopher's home
SolidWorks Legion
RE: SI units tol
If the number (x) falls within the range...
RE: SI units tol
Thanks, I typed too fast without checking.
Chris
SolidWorks 10 SP5.0
ctopher's home
SolidWorks Legion
RE: SI units tol
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: SI units tol
Of all my years of drafting/eng/etc, this is the first I have seen this.
Chris
SolidWorks 10 SP5.0
ctopher's home
SolidWorks Legion
RE: SI units tol
There was an ANSI or ASME standard on metric tolerancing that proposed the ISO style, (DIN German) system it appears to have been withdrawn now.
Frank
RE: SI units tol
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: SI units tol
Powerhound, GDTP T-0419
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Inventor 2010
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RE: SI units tol
It was happily reassured in 2004 but later decision was made to transfer it from B4 committee to Y14 committee to become "drafting and tolerancing" standard.
As a result it was successfully "missing in action". Copies are still around. One may be surprised, how much it resembles ISO 2768.
RE: SI units tol
Frank
RE: SI units tol
Example; 14.0
14.00
14.000
General Tolerances
.X = +/- .01
.XX = +/- .001
.XXX = +/- .0001
Above shown is just an exapmple. You might be familiar with this.
If you use milimeters (mm) in the drawings then the whole numbers should not be preceeded by zeros as per the satandard. You dont have provision to assign general tolerances as the example shown above. Since ISO standard uses mm as the dimensioning unit. it has to go for other methods for mensioning the genereal tolerances. The general tolerancing scheme you mentioned in your post is very coomon in ISO.
RE: SI units tol
Do you work with the ISO system much, yourself?
Frank
RE: SI units tol
I am very familiar with the scheme you mention.
Chris
SolidWorks 10 SP5.0
ctopher's home
SolidWorks Legion
RE: SI units tol
Frank
RE: SI units tol
What are your doubts/concerns about ISO system?
RE: SI units tol
Yes, I wrk on ISO system. We use Geometrical Product Specification (GPS) in our drawings. GPS is based on ISO standard constisting of more than 150 standards to completely define the part. It is very similar to GD&T,(but there are few differences compare to ASME standard). In our companey we dont use general tolerances in drawings. But I have seen many drawings created as Chris mentioned in his post.
RE: SI units tol
Thanks, I think you know I have been interested in it for some time. I do not feel I know enough about it to have my own "doubts".
Madhu454,
Thanks, I sounds like you do not use the part we have been discussing here, I have been interested in issues like the stack up of these implied tolerances.
Frank
RE: SI units tol
Yes, I noticed that you are really interested in the ISO GD&T language, or as Madhu454 said - GPS. And I also noticed that you sympathize with some (or most?) of the ISO's approaches to the tolerancing of parts.
I also remember that you already started some threads about the topic on the forum. The most recent one was about cummulation of tolerances for two round holes, right? Could you give any other example showing your concerns? I think it would be a best starting point for further discussion.
RE: SI units tol
I don't understand your confusion.
My initial post is different than what Madhu454 had written, which I have used for 30 years.
Chris
SolidWorks 10 SP5.0
ctopher's home
SolidWorks Legion
RE: SI units tol
I am very sorry, I must be confused about the subject of your initial post:
"How do you read these tolerances?"
"I have never used this type before."
I thought you were refering to ISO type tolerances.
Frank
RE: SI units tol
Frank
RE: SI units tol
What do you want to discuss about ISO 2786-1 in particular? It is still too general subject for a discussion. There is also 2786-2. Is it something you wanted to talk about too?
RE: SI units tol
I believe the determination was made, basically by concensis, that the general tolerances must be accumulative if you are looking at a worst case stack-up? Do we have any validation of that outside of our own conjecture?
There are also ISO standards covering casting and welding that are similar. These seem much more realistic to me than what we use and I am interested in the opinion of people who use these to they find if it works well for them?
Frank
RE: SI units tol
The ISO discussions could go here:
thread1103-298244: Tolerances of ISO 2768 cumulative or not?
Frank
RE: SI units tol
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: SI units tol
Unfortunately for me, but fortunately for you, no further posts about ISO 2768 showed up in this or other thread on the forum.
RE: SI units tol
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: SI units tol
In fact, whether features are done in the same set up is perhaps more of a factor these days.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: SI units tol
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: SI units tol
This subject keeps popping up here and there is still confusion.
If I have dims 10, 10.2, and 10.425, what are the tolerances per the tol block?
I get mixed answers. I'm not used to these type of tolerances as displayed per ISO.
Chris
SolidWorks 11
ctopher's home
SolidWorks Legion
RE: SI units tol
A dim of 10.3 gets ± 0.15
A dim of 10.425 gets ±0.15 (or ±0.150)
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: SI units tol
10.2 +/-0.15
10.425 +/-0.15
----------------------------------------
The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: SI units tol
Not 100% clear.
Chris
SolidWorks 11
ctopher's home
SolidWorks Legion
RE: SI units tol
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: SI units tol
Chris
SolidWorks 11
ctopher's home
SolidWorks Legion
RE: SI units tol
Frank
RE: SI units tol
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: SI units tol
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: SI units tol
Example:
.X = +/- .02
.XX = +/- .01
.XXX = +/- .005
This is not the same as the below if the decimal places in the tol block are different, only if they are as the ISO stated previously.
10.2 +/-0.15
10.425 +/-0.15
It's just as simple as I'm not used to using ISO.
Chris
SolidWorks 11
ctopher's home
SolidWorks Legion
RE: SI units tol
Frank
RE: SI units tol
From table 1 of ISO 2768-1, a dimensions of 25mm would have the following tolerances based on tolerance class.
f 24.9-25.1
m 24.8-25.2
c 24.5-25.5
v 24-26
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RE: SI units tol