Tried googling and didn't come up with much on this. Say you have a flat-bottomed bore that's 1.000" diameter, 0.750 deep from a flat top surface which is used as Datum A. Inside that bore, you have another feature, which is a 0.250" drilled hole (eccentric to the bore), that is 1.250" deep from Datum A (or 0.500 deep when measured from the bottom of the bore).
Is the correct way to call out the depth of the 0.250" hole:
1. In a "top-down" view of the bore (ie you are looking directly into the bore) with a callout of "∅0.250 down 1.250"
2. In a "top-down" view of the bore with a callout of "∅0.250 down 0.500" (since the top of the 0.250 hole is at the bottom of the bore)
3. Use a section view to describe it specifically using linear dimensions
4. Other
I ask because in certain cases, either 1 or 2 could be considered ambiguous unless there is a drawing standard that says you would always use one or the other.
Is the correct way to call out the depth of the 0.250" hole:
1. In a "top-down" view of the bore (ie you are looking directly into the bore) with a callout of "∅0.250 down 1.250"
2. In a "top-down" view of the bore with a callout of "∅0.250 down 0.500" (since the top of the 0.250 hole is at the bottom of the bore)
3. Use a section view to describe it specifically using linear dimensions
4. Other
I ask because in certain cases, either 1 or 2 could be considered ambiguous unless there is a drawing standard that says you would always use one or the other.