Checking backplate for runout?

[ome]

Hi guys,
not sure if i am suppose to put indicator probe on outside edge if plate or the front side that will go inside the chuck onced bolted together.
Checked the face clear above the bolt holes, within one thousand out.
Thanks
jon

 

[aforsman]

You may want to check out this thread - http://www.hobby-machinist.com/newreply.php?p=149588&noquote=1

I had similar questions and there's a lot of good info there, though it digresses toward the end.

 

[ome]

It's generally a good thing to have zero runout anywhere on a backplate so it rings alarm bells if it develops some at a later date. Also no balance worries. That said, the only really critical area is the chuck register,

Before you do any skimming, it may be worth taking the plate on and off a few times and check the repeatability of your reading, and to be absolutely certain that it's mounted properly.

Is this what you meant?

Yes, exactly. When you say on proerly do you mean threaded evenly. And square to the shoulders.
Thanks,
jon

 

[ome]

Yes, just nicely home with a solid "snap" at the end, with the indicator showing the same reading each time. One tiny bit of swarf will really confuse things. It's all about repeatability.

Thank you very much
jon