Significant units used for thru hole dia and c'bore dia and depth

[lonsgsp]

Is it permissable to use a mix of 2 and 3 place decimal dimensions units (inch)in the same callout example 3 place decimal for thru hole tolerance and 2 place decimal for c'bore diameter and 2 place decimal for c'bore depth. ASME Y14.5 2009 states that in using bilateral tolerances all units must have the same number of significant digits. It does not mention anything about using the same amount of digits for use in counterbores and countersinks.

Thanks

 

[fsincox]

They do not really cover that kind of thing, other than to say the tolerance should match in decimal places, as you say.
Frank

 

[pmarc]

Short answer - no, there is no such requirement in Y14.5-2009 forcing you to use the same number of decimals for diameter of thru hole, diameter of c'bore, c'bore depth. So, I am with Frank on this.

 

[KENAT]

Are these call outs related to a single FCF? If you have a counter-bored hole with a position FCF then I think the diameters to which the position tolerance applies need to match the number of decimals in the FCF right? In that case the number of decimals of the counter-bore diameter should match the decimals of the hole. Or am I making things up again?

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[pmarc]

There is no such requirement in Y14.5, Kenat.

 

[TWJR]

Where decimal places need to match is the FCF and corresponding basic dimension(s). Size dimensions can be anything.

 

[pmarc]

TWJR,
This isn't requirement per Y14.5-2009 any more.

 

[KENAT]

Guess I have been imagining/making up stuff and didn't have 14.5 to hand.. ASME Y14.5M-1994 2.3.2d is probably what I was thinking of.

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[lonsgsp]

The 2 versions of ASME Y14.5 1994 and 2009 read the same in 2.3.2 and the referenced paragragh 1.6.1. 2.3.2 deals with displaying the tolerances of a certain distinct feature. Thinking about it (should have done that in the first place), a common C'bore hole has 3 distinct features; thru dia, C'bore dia and C'bore depth. Each one of those is a separate distinct feature with its own tolerance and can therefore be different. This could also be the same when dimensioning C'sinks

Thanks all for the input

 

[TWJR]

pmarc: Good to know that it isn't required any more in 2009, but we're using 1994, hence my not knowing that.