Datums for Castings

In this Question Line video, Jason answers the following question regarding datums for castings: 

I am trying to understand what the purpose of this generous position tolerance back to a cast datum is for. The cast holes are used for machining set up.

Jason discusses the submitted drawing below, as well as presenting another example that he uses to talk about how datum targets, datum reference frames, and multiple datum structures can be of assistance in casting drawings.  

Looking for answers to your GD&T questions? Submit your question to our GD&T experts at the link below!  

https://www.gdandtbasics.com/share-your-gdt-questions/ 

If your question is selected, we will notify you when our video answer is posted to our YouTube channel.  

* If you are a current student, reach out to us directly and we will get you into contact with your instructor. Active students’ questions receive a direct response within 24-48 hours.