Reference datum on position and profile callout 2

[SeasonLee]

Please ref to the attached sketch, there is no doubt a reference datum should be on the perpendicularity callout, my questions :

1. Are there any problems on the 2nd hole referenced datum? Why not include the planar datum B?
2. Can we call out the profile with referenced datum A and C as shown?

Thanks for your assists.

Season

 

[Tarator]

I agree on B/A/C GD&T scheme. However, I wouldn't use the whole planar surface as datum feature B. I would use target areas around the datum feature A (both sides!!!), so the datum B would be the center plane. According to what I get regarding the function of this part, that seems to be the best approcah to me.

 

[SeasonLee]

Thanks for all inputs, had made changes based on our discussion, please let me know should you have any further comments.

Season

 

[slipstream44]

Please re-think your + .005/ -.000 lower tolerance for the .190 dia DATUM A. If you wish to keep it, you should add MMB in the FCF.

 

[Belanger]

Slipstream -- do you mean MMC, rather than MMB?
(Datum A, where referenced, already has MMB. And the perpendicularity of that hole can't use MMB because datum B is a plane.)

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[SeasonLee]

We all agreed the DRF would be B|A(M)|C, and I am trying to talk with our customer to accept it, if our customer says they prefer to use the hole as primary datum, i.e. A(M)|B|C, then how will you convince the customer to accept our scenario B|A(M)|C (based on the function of the part as I posted at 10-16-13). Thanks for the inputs.

Season

 

[Tarator]

What are you "selling" to your customer? Your design or you manufacture the part for them?

 

[SeasonLee]

We are an OEM supplier in Los Angeles California, the part manufactured in Asia, the original design with plus and minus toleranced was made at 1990, now they are trying to convert it to a GD&T toleranced part, from the earlier posts you will agree the customer encountered some problems on the print converting, I am just trying to help them to do it correctly.

Season