Units in a feature control frame?

[legrand01]

Our head of drafting is saying that it's not acceptable to put units in a feature control frame, i.e. we have some tolerances where the number would be listed as .000005 and we'd like to put 5μin instead. I think that the standard doesn't outlaw it, so it should be fine to use the 5μin.

Who is right?

 

[drawoh]

legrand01,

I would say that if the standard does not explicitly ban it, it is legal.

Your titleblock note should say something like "UNLESS OTHERWISE SPECIFIED, ALL DIMENSIONS ARE IN ROYAL CUBITS". Your FCF specifies otherwise.

--
JHG

 

[KENAT]

The standard doesn't outlaw it that I can recall.

So then fall back on the second argument of does it add or detract to clarity/likelihood of misunderstanding...

Perhaps the 'μ' might look like an 'm' or something to some users of the drawing.

Perhaps the compromise is to put all the 0's. Then in parenthesis next to the fcf have the (5μin).

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[powerhound]

or 5E^-5

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[ArvindHalashi]

I never seen adding this, so that is not correct. We should specify as KENAT suggested

Regards,

Arvind
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[MechNorth]

Kenat is right about the lack of clarifying value, but I would not add the (5uin); it would be too easily misunderstood or not comprehended at all.

Jim Sykes, P.Eng, GDTP-S
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