Dial Indicator Attachment

[mklotz]

I think this...

Homemade Mitutoyo-type 'Zero It' Indicator Holder - HomemadeTools.net

is probably the article to which metric_taper refers.

The Zero-it is a very nice tool but at prices approaching $200, one is strongly motivated to make one's own copy, or, better yet, make Doug's design.

BONUS HINT:

Since I just addressed this on another forum, I'll repeat it here.

Lots of folks, when using a device like these, fiddle about with mirrors to see the DTI dial when checking the +Y point of a hole/pin over which they are centering the spindle.

Assuming that the hole/pin is truly cylindrical (i.e. circular cross-section), if the +X, -X, and -Y DTI readings are the same, the +Y must read the same (i.e., it need not be checked). This is a consequence of the geometric fact that three points determine a unique circle.