Measuring runout on a shaft relative to two datum surfaces 1

[PetkovStoyan]

Hi everyone,

I am struggling with one practical issue how to measure shaft runout, when two datums are specified simultaneously, having different diameter size. Can this be achieved only on a lathe with dial indicator? Is it possible to align both diameters this way, without using custom made jigs?

And in general, is it ok to use the lathe and dial indicator to align along a datum, even if it is single datum diameter? Is this practice legit and valid?

Drawing attached

https://files.engineering.com/getfi...-4246-9516-1899c1f8f3da&file=GD_T_Problem.jpg

 

[PetkovStoyan]

ground - creating using a grinding process.

Thank you for the clarification, as "ground" means also "base", or "floor", it was confusing to me. The "journal" part was clear to me

Not sure how to restrain the part axially - I don't know what you have access to or what the entire part looks like.

I don't have access to anything fancy, I think I will use steady rest on a lathe to support datum "B", and the left machining center-hole, which should get datum "A" aligned, since they are very close. Then I have to use four-jaw chuck, with independent jaws to clamp the part and restrain axial movement. Otherwise, If I use self-centered chuck, there is no guarantee that it will clamp the part dead center.

EDIT: Or maybe two separate steady rests for both datums is more appropriate?
Please share your thoughts on that. Thank you.

Image of the complete part is attached.

https://files.engineering.com/getfi...23f-1cd845a45508&file=2023-08-10_Untitled.jpg