tolerance for patterned holes

[idanbrk]

hi all,

I'm designing a part that has 20 holes in it in a 15 mm distance from the datum A (see in attached picture) , whats important to me is that all the holes centers will be on the same plane within 0.01mm , i dont want to place a +-0.01mm tolerance on the 15 dimension because its not important , the holes can be even 16 or 14 mm away from the base but whats important is that the centers will be on the same plane , what is the correct way to write that on the drawing?

thanks

 

[drawoh]

idanbrk,

Select two holes, and make them your secondary datum[ ]B and tertiary datum[ ]C. Put a sloppy profile all around your 210x30mm outline.

--
JHG

 

[Tunalover]

I would use a width datum as the primary datum.


Tunalover

 

[Vishal2015]

Hi Idanbrk,

I think you can use composite position tolerance with pattern relating tolerance zone of dia 0.02mm.

Refer to attached image.

Vishal.

 

[KENAT]

My first thought was also composite position for the hole pattern. You could go Drawoh's route but you still need to tie the holes together.

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[CheckerHater]

Composite, the way Vishal described it

"For every expert there is an equal and opposite expert"
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[idanbrk]

thanks everyone , you have been very helpful