continuous diameter as temporary datum feature?

[bxbzq]

The wheel in attached drawing has two steps mfg processes. Water cutting by a supplier to cut the spoke then machining in our shop to make center hole and outer diameter. The scenario is similar to casting vs. machining. On the water cutting drawing I need a temporary datum features to establish datum axis. I select the root dia of the spokes. Can I treat that dia. as CF dia. and use it as a datum feature? Do the datum callouts in the two drawings make sense to you?

We work to Y14.5-2009.

 

[DeanD3W]

Yes, I believe <CF> (10 SURFACES) placed by the datum feature B symbol would work fine. As an alternative, you could use the OD as datum feature B instead, with a similar CF modifier, then reference B also (so [A,B]) for your 10 profiles from X to Y.

Best Regards,
Dean

http://www.d3w-engineering.com

 

[pmarc]

I agree with Dean that technically CF modifier could be associated with datum feature B on the water cut drawing (although physically the 10 dia.50 surfaces were not formed from a single feature).

The alternative - OD as datum feature B instead, with a similar CF modifier, then reference B also (so [A,B]) for your 10 profiles from X to Y - is a choice too.

I have another one: get rid of B completely and control everything (that is the spokes and the outer interrupted diameter) with relation to A only. Simultaneous requirements will do the rest.

 

[bxbzq]

Is using the OD 184 as temporary datum a good practice? Reading through para 4.3.1 of Y14.8, I tend to think the dia.50 is a better option for the temporary datum feature.

 

[pmarc]

Yes, I agree. The OD 184 isn't the best candidate for a temporary datum feature.