Bad drawing conversion (hole pattern asymetric position) 1

[Joel_Lapointe]

Currently working on a part mod. I want to convert the current drawing to proper GD&T standards.

So, a 6 holes pattern of 6mm H7 is positioned on a pitch circle of 25.78 which has asymetrical tolerance.

So, I want to convert this asymetrical tolerance of (+0.012, -0.006) mm to a position tolerance. The pitch circle is now "basic".

Is there a proper way to convert?

 

[3DDave]

You have two tolerances. An angular tolerance that you haven't included and a radial tolerance that is part of the pitch diameter tolerance. What you did not have originally is an indication of what the pitch diameter was located from.

You can create bidirectional position tolerances, one radial and one tangential and figure the tangential tolerance using trigonometry from the original angular tolerance and the radius, to more adequately represent the situation.

Since the original fit was unlikely to be diametral a diametral position tolerance likely won't be appropriate.

 

[drawoh]

Joel_Lapointe,

If you change your pitch circle to Ø25.783, you can apply a symmetric tolerance, and convert to positional tolerances.

--
JHG

 

[Joel_Lapointe]

drawoh,

Good Idea!

Thank you...

 

[3DDave]

Looking at the conversion image - you have clearly shown there is zero location tolerance at all.

Pretty good if you can get the machinist to do that.

 

[Joel_Lapointe]

I've put zero because I need to change it accordingly...

 

[3DDave]

Do you want to learn or just get an answer?

 

[Wuzhee]

Ø0(M) would make sense but I doubt it helps you.

 

[Burunduk]

Do you want to learn or just get an answer?

This is eng-tips, not eng-preachings.

 

[3DDave]

You can do the work for him or spend the time creating a tutorial, but you choose to snipe.