Datums on circular features

[Avital]

Hi,
I am trying to set a hole as a datum reference to another set of holes but can't work out how to set up a datum reference on the first hole. Does anyone know how to set it on the hole surface.
Cheers!

[willwad]

Not sure exactly what you have in mind. You can set an axis (presumably, the axis of revolution for the hole) as a Set datum (in WF3.0, right-click on the axis-->Properties). Then you can call out GD&T referencing the datum axis on the drawing.

If you're trying to create an axis on the hole surface itself for whatever reason, you will probably have to create a couple of points on the surface and then create an axis through the points.

You may need to include a little more information if this doesn't answer what you're getting at.

[Gearbox]

Hi,
You can attach it to the hole diameter dimension.
Cheers!

[pro_climber]

Avital,
Can you post a pic? If what you want is to create a datum plane passing thru two holes, you can do it by creating a datum plane passing thru the two axes. If it is something else, please post a pic.

[street_preacher]

You have two options, use the existing hole axis and redefine it, or create another axis through the hole as the datum axis. I will try to explain both.

The first method involves selecting the original axis of the hole you want to use a datum and choosing Properties. You can change the name, type and placement. You will want to choose one of the two datum types depending on your standards, then you will want to choose the In Dim placement type and choose the hole diameter for the hole you wish to use as the datum.

The other method is similar but you Insert a Model Datum: Axis first. I think that if you do this in drawing mode, it Automatically changes your type, but I'm not sure. Just be sure in both methods that you set the type to a Datum type and choose your placement correctly.