opinions needed!

Forum|Forum|15 years ago
August 31, 2010
12 replies
7751 views

When a hole is on a round surface, and they share the centerline, there
is no dimension to locate it from side to side (the .000 dim). How is a
tolerance applied to the location of such a hole (without using a gd&t
position callout)?

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2D Drawing

D

dgschaefer

21-Topaz II

No idea if this follows any sort of standard, but what about a note
saying "HOLE C/L MUST BE WITHIN +/-0.005" OF SHAFT C/L" or something
like that?

Doug Schaefer

S

schelld

1-Visitor

1. Remove the .000 dimension.

2. If you want the hole dimensioned with a tolerance, then, add a
dimension from the outside surface to the hole.

J

joepaul88

1-Visitor

I have raised this question before internally also, there does not seem to be any experience with this from anybody I talk with. Personally I feel that like 90° angles, this sort of feature is "understood" to require the tightest standard "sheet" tolerance, i.e. .xx=±.03 / .xxx=±.015, the location would be ±.015.

Otherwise, if you need to control it beyond that, GTOLs would be the way to go as they are understood (sort of) by most everybody who would need to read the print.

J

JOES

1-Visitor

Assuming the tolerance is +/-.005 for both the .333 dim & the diameter of
the shaft, the center of this hole is in a .010 square tolerance zone. .005
all four ways.

Regards,
Joe S.

On Tue, Aug 31, 2010 at 1:19 PM, Doug Schaefer <
> wrote:

> No idea if this follows any sort of standard, but what about a note
> saying "HOLE C/L MUST BE WITHIN +/-0.005" OF SHAFT C/L" or something like
> that?
>
> *Doug Schaefer*
>
>
>

D

dgschaefer

21-Topaz II

That puts 2 dims in the tolerance stack, the shaft dia. tolerance and
the positional tolerance of the hole to the edge.

Doug Schaefer

C

columicious

Author

1-Visitor

Thank you for all your opinions!

I think, to avoid any possible confusion, the tolerance has to be on the
.000 dimension. (or of course to just use GD&T)

I do agree that the untoleranced, undimensioned feature could by default
go to the sheet tolerance, but think it would still be unclear whether
it be the tightest or loosest sheet tolerance.

P

pgress

1-Visitor

I don't understand, why don't you just add a true position tolerance to
the hole diameter callout? Whenever a feature is placed on a centerline
it's referenced from there.

Paul

1_blankfilename.txt

J

jnanesh.sajjan

1-Visitor

To be honest I have not come across such requirement so far. I feel
without giving GD&T, it is difficult to control.

I am not sure whether I am correct but my idea would be to give a
position tolerance for the lateral hole. See attached image. I think we
may have to add another tolerance to the hole - a runout with respect
axis of hole.

Thanks,

Jnanesha KS