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Missing Tolerances
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5not4 View Drop Down
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Joined: 09 Jul 2013
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    Posted: 18 Feb 2015 at 9:07am
Is there a 'typical' tolerance to be used when there is no value given on a datasheet?
 
For example - I need to make a footprint for OSCCC style crystal but no dimension is given for the D1 / E1 values (gap between the feet). 

Nominal values are provided for foot width (X and Y) so the gap between can be calculated easily.

What tolerance should be used for an accurate footprint?
 
Any and all comments welcome and greatly appreciated.
 
Datasheet example
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Tom H View Drop Down
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Points: 5719 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 18 Feb 2015 at 9:52am
Tolerances are normally +/- 0.20 mm for larger dimensions and between +/- 0.10 & 0.15 mm for small dimensions.
 
However, for the Corner Concave component family I tend to use the mfr. recommended pattern.
 
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5not4 View Drop Down
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Points: 40 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 5not4 Quote  Post ReplyReply Direct Link To This Post Posted: 18 Feb 2015 at 10:31am
Good information, Tom!
 
Thanks for the quick response.
 
Roy.
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