Applying the appropriate tolerance..

[soupy1957]

On a few of our prints, from time to time, I note that our Drafting group has used dimensional callouts with single-digit characteristics, such as "2.0" for example.

In our typical "standard" Tolerance chartings, there is no tolerance criteria for a dimesional callout for this type of number.

We obviously would use ±.01 for a ".00" number, and ±.005 for a ".000" number.

What tolerance would YOU apply to a ".0" number?

-Soupy1957

Telepathy only enhances the world I live in!!

 

[ewh]

I wouldn't. I would ask for clarification from the originator.

 

[PSE]

I agree with ewh, without a reference or standard available, your best recourse is to go back to the individual who designed it.

Regards,

 

[debodine]

We used to have this issue occcasionally until we finally added a tolerance for a "one digit to the right of the decimal place" dimension to our drawing template.

For our purposes our tolerance chart now looks like this:

3 PLACE (.xxx) DEC = +/- .010
2 PLACE (.xx) DEC = +/- .03
1 PLACE (.x) DEC = +/- .1

These are the typical tolerances that work in our industry (aircraft after market modification), and of course a drawing note can always override these standard tolerances for any given dimension.

debodine

 

[KENAT]

thread404-201568

KENAT, probably the least qualified checker you'll ever meet...

 

[KENAT]

Oops, hit submit not edit.

As you may see from my reply to your other post, I'd tend to agree with ewh & PSE.

I'm not sure why you say "We obviously would use ±.01 for a ".00" number, and ±.005 for a ".000" number.". Why is this obvious? Is this what you standard tol block says?

I've seen lots of tol blocks saying something different, I've also seen separate tolerance standards referenced, also tolerances based on size of feature, a single value regardless of decimals and no tolerance block with every dimension directly tolerance by +- or limits.

The tolerances for each dimension should be based on function, with manufacturability an important secondary concern. They should not arbitrarily be asigned based on decimal places without the function being considered.

There's a different between determining values for, and specifying tolerances.

I'd go back to your drafting department and ask them, based on function, what the tolerance should be.



KENAT, probably the least qualified checker you'll ever meet...

 

[YARAK]

IF IT IS AN INTERNAL DWG, GET WITH DRAFTING. I WORK IN THE AERO SPACE INDUSTERY, ONE OF OUR CLIENTS HAS THIS IN THEIR TOLERANCE BLOCK

.XX +-.03
.XXX +-.02
.XXXX +-.03

I DID A DOUBLE TAKE AND A HEAD SCRATCH, THEN CONFIRMED THE BLOCK WITH MY BOSS. ITS THE WAY THEY WANT IT.

MIKE

 

[KENAT]

Yarak, now that's weird.



KENAT, probably the least qualified checker you'll ever meet...

 

[monkeydog]

YARAK,
Try and get with your customer, or get with your sales person to get with your customer.
It is fat finger mistake.
Your customer would appreciate the clarification, rather then have you make it to print, then have to scrap and remake it.
If not for the cost, then for the schedule hit.

 

[KENAT]

monkeydog, I took "ITS THE WAY THEY WANT IT" to mean his boss had talked to the customer and it's the way they want it.

KENAT, probably the least qualified checker you'll ever meet...

 

[YARAK]

THE CLIENT CAME DOWN, BEFORE I STARTED HERE, AND HAD A MEETING WITH QC TO VERIFY THE BLOCK.

ITS A BIG CLIENT THAT IS GOING TO BE LATE WITH THE NEW AIRPLANE THEY ARE BUILDING.

IS THAT HINT ENOUGH?

 

[KENAT]

YARAK, NO NEED TO SHOUT;-)

Hmm, gee let me see. Late with the new airplane they are building, as opposed to late with the one they've just built.

No I can't work it out;-)

KENAT, probably the least qualified checker you'll ever meet...

 

[underspec]

The usual tolerances I see are:

X. +/-.015
XX. +/-.010
XXX. +/-.005
XXXX. +/-.0005

This is of course not metric.