Standard Tolerance(in the title block) a comparsion from mm to in

[humanbone]

I work in an environment where we use metric units and English dimensions on different drawings. We use the English dimensions on the tooling drawings (vises, cutters, etc). Then we use metric dimensions for the actual product we manufacture with the tooling. So to my question. Do the standard tolerances in the title block have to be the same, from metric units to English units? Here is what we have now

English
.xx +/- .03
.xxx +/- .010
.xxxx +/- .0020
Angle +/- 1

Metric
.x +/- .6
.xx +/- .20
.xxx +/- .030
Angle +/- 2

From my past understanding, these have to be the same value from one another, same decimal places, everything. What do you all think? Thank you

 

[wes616]

Why would they be the same. Your tooling tolerances can (and probablly will) be different than your product definition tolerances.

Wes C.
------------------------------
Light travels faster than sound. That's why some people appear bright until you hear them speak.

 

[ringman]

What is the Standard that you are applying for your dimensioning and tolerancing? Would that not answer the question for you?

 

[looslib]

You have a conflict with the standard for metric dimensioning that says no trailing zeros on metric values.
Metric
.x +/- .6
.xx +/- .2
.xxx +/- .03
Angle +/- 2


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli
Sr IS Technologist
L-3 Communications

 

[ctopher]

What you show is acceptable.
As Ben described, remove the trailing zeros.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[fastasleep]

Why did your angle tolerance change? Are you dimensioning in Grads?

 

[ctopher]

fastasleep, Good catch!
I didn't look close enough.
Angle should be the same, unless you specify the difference.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[wes616]

Regarding the angular tolerance

Again, I want to point out that the OP stated that the two different unit systems are for entirely different products (metric for product, us customary for tooling). Each product may have a different set of "standard" tolerances as defined by the manufaturing/engineering/inspection requrements.

I just don't see this as an issue whatsoever.

Wes C.
------------------------------
Light travels faster than sound. That's why some people appear bright until you hear them speak.

 

[humanbone]

Ok so i guess i kind of answered my own question(i just needed some to actully tell it to me). The metric units is for the product and the english is for the tooling. So who cares if the tolerances are different because we would never chris-cross the two (ex: i would never dimension tooling in metric units at this job). so i wont change a thing. Thank you

 

[wes616]

Humanbone, you should follow ben's advice regarding the trailing zero's though.

Wes C.
------------------------------
Light travels faster than sound. That's why some people appear bright until you hear them speak.

 

[humanbone]

yeah, that was a mistake i made when i was writing the thread itself. we dont have trailing zeros

 

[LONDONDERRY]

No Good bro.

English tolrance should be based on decimal and metric on unit length or ISO 2768. Here's what I use for my metric drawings

UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN MILLIMETERS
IN ACCORDANCE TO ISO 2768-mKE

0.5 UO TO 3 +/- 0.1
OVER 3 UO TO 6 +/- 0.1
OVER 6 UP TO 30 +/- 0.2
OVER 30 UP TO 120 +/- 0.3
OVER 120 UP TO 400 +/- 0.5
OVER 400 UP TO 1000 +/- 0.8
MACHINE ANGLES +/- 0.5 DEGREES
MACHINE FINISH 3.2RMS
CORNER RADII 0.2MAX
CORNER EDGES 0.2 MAX

 

[looslib]

Yes, you are correct IF humanbone specifies ISO standards. If he specifies ASME Y14.5m-1994, then his original tolerances, with corrections, stands.

We used ISO 2768-mK, when we switched to ISO standards.

"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli
Sr IS Technologist
L-3 Communications

 

[JohnNabors]

Also, it states in para 1.6.1(a) of ASME Y14.5M-1994 "Where the dimension is less than one millimeter, a zero precedes the decimal point."