Hole Position Tolerance Question
Hole Position Tolerance Question
(OP)
Hello,
In the attached jpeg, There are two datums defined for the position of the Diameter 5 holes. The GDT box defines the position of the holes with respect two Datums A, B and C.
There is no defined relation for the location of Dia. 5 holes with respect to Datum C (dia 3 hole). How are the location of the Dia 5 holes effected wrt to Datum C? How should the tolerance table for these holes shape up with respect to changes in the datums?
Best regards
In the attached jpeg, There are two datums defined for the position of the Diameter 5 holes. The GDT box defines the position of the holes with respect two Datums A, B and C.
There is no defined relation for the location of Dia. 5 holes with respect to Datum C (dia 3 hole). How are the location of the Dia 5 holes effected wrt to Datum C? How should the tolerance table for these holes shape up with respect to changes in the datums?
Best regards





RE: Hole Position Tolerance Question
This drawing is one of the better ones out there and it reflects that the Designer has a relatively good understanding of GD&T.
Dave D.
www.qmsi.ca
RE: Hole Position Tolerance Question
What I understand from your explanation is the Datum C only relates the orientation of the two holes. It does not express any relation with respect to dimensions.
In the attachment, there is a slightly modified orientation of the holes. What do you say about this version. Is it correct in terms of meaning usage considering the tolerance of the holes with respect to Datum C?
RE: Hole Position Tolerance Question
Dave D.
www.qmsi.ca
RE: Hole Position Tolerance Question
It's just the basic angle dimensions are "invisible"; 0 deg and 90 deg basic angles are usually IMPLIED.
From the appearance of the dimenssions the drawing is coming from ISO country. Does anybody know if there is big difference between ISO and ANSI/ASME when it comes to implied angles?
RE: Hole Position Tolerance Question
The drawing is indeed taking advantage of implied 90°.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Hole Position Tolerance Question
RE: Hole Position Tolerance Question
It was my general impression, but it is always better if someone knows for sure. :)
RE: Hole Position Tolerance Question
Best regards,
Oykun