Correct GT&D for bore on vertical centre line
Correct GT&D for bore on vertical centre line
(OP)
I need some help on a part I am designing. I have a cylindrical part with two ODs, I need a hole to be located on the smaller OD (tolerance of +/-.002") and centred on the vertical centreline of the part (also tol +/-.002). I know that I cannot use a centreline as the datum and am wondering on the correct way to dimension this part. Thanks for your help





RE: Correct GT&D for bore on vertical centre line
Whatever this feature is needs to become a datum most likely.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Correct GT&D for bore on vertical centre line
You need a feature to define your centreline. You can use your hole to define it. The only tolerance you need is the location on the circle.
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JHG
RE: Correct GT&D for bore on vertical centre line
Thanks for the quick response.
The feature that defines the vertical centreline are two other holes at 45 degrees as shown in attached sketch, however I am not sure how to use these features to define a datum.
RE: Correct GT&D for bore on vertical centre line
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Correct GT&D for bore on vertical centre line
Also what is the correct way to show that the hole is located on the diameter and include the tolerance?
RE: Correct GT&D for bore on vertical centre line
It is legal to call up each of the tapped holes as a datum, but it will be a pain to fixture in the shop. Why not use your bore as a datum, and locate everything else to it, as we are suggesting, above?
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JHG
RE: Correct GT&D for bore on vertical centre line