We’re looking at a digital indicator available from B.G. Micro. The best part about this tool is the mounting holes. I can’t tell you all the time I spent cutting off or drilling holes in the stainless steel jaws of regular calipers in order to mount them to my milling machine to act as digital readouts.
Cutting off caliper jaws (top, blue arrows) or drilling holes (bottom, green arrow) through stainless steel to mount.
In comparison, this digital indicator has:
Bottom side mounting holes
The 3 mm slide screw hole (pictured below) is nearly the same size as a 4-40 screw, such that an American might try jamming one in. Please don’t. It will work for the first couple of threads and then stop.
Slide attachment screw holes on sides
To show you what a quality piece this is, there are two gib adjustment screws to ensure smooth travel of the slide. Additionally, a thumb screw can be added to lock the slide at a particular position. This is probably an artifact of reusing a caliper body, and is unnecessary for a test indicator.
Top side mounting holes gib adjustment and slide lock
The slide physically stops at the beginning and end of its maximum range. There is no need to fear it popping out if you move it too far.
Spring return on indicator slide
The spring can be detached via a screw if you want to disable it. However, it may or may not be possible to reattach it.
Finally, let’s examine the data output of the tool.