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!


Active Member
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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