GD&T

[[SH...]]

Can I ask what is the real meaning of datum feature translater (triangle symbol near datum). Unlike MMB it has no limit for translation?

[[Ja...]]

That's a new one to me. This is what I found.

Doc1.pdf

[[Ja...]]

It's also explained in ASME Y14.5 2009, Fig. 14-9.

[[SH...]]

Yes, 2009 standard introduced this concept, if a datum has this symbol it means it can control only rotation, can't translation. This what l understand. But degrees of constrain symbol( x y z u v w)can do same function.

[[Ri...]]

viewtopic.php?f=13&t=3586

TL-DR: It's only used for making mechanical/functional testing gages - it does not apply to CMMs.