Mitutoyo test indicator dovetail stem stuck

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Oct 9, 2017
Hey all, just picked up a Mitutoyo 513-406 test indicator off eBay, and while it seems to be in good condition, I'm a bit puzzled on the stem that is attached to the dovetail. It seems impossible to remove. Came with 2 stems, an 8mm and a 4mm. The 8mm one is like I expected, just a screw into the dovetail stem holder, slide it over the dovetail, tighten it down, off you go.

The 4mm was on it when it arrived. It was way tighter than I expected, but I finally got the stem to unscrew from the holder. But there is still a ... post (?) buried in the dovetail stem holder, and the stem itself is more like a collet in that the threaded part is actually split in 2 places. Anyway, with the stem removed, the stem holder remains firmly attached to the indicator.

As I gradually build up my basic set of machine tool paraphernalia, this is my first test indicator, so I would not be at all surprised to learn that I'm missing something! So, how am I supposed to get it off? The Mitutoyo drawings suggest it is not a permanent part.

Here it is as it arrived...


Thanks for any help!


H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
May 4, 2019
The stem threads into the dovetail adapter. It presses on top of the dovetail to lick into position. Hold the stem in a vise with padded jaws. Rotate the indicator body to back out the stem. One turn should be enough.
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