Height gauge addition.

[mklotz]

Here are some modified calipers. On the left I have cut off the OD measuring jaws, which allows it to fit some bores to measure grooves or spacing directly. The second one has been shortened to allow it to fit into smaller spaces, the usual depth gauge rod has been cut off also. A small bolt has been added at the end to act as a stop. The stub of the cutoff depth rod will bear against the bolt so the plastic case is protected.
The other two have just had the jaws modified to allow them to be used where there would otherwise be some interference.

I like all your caliper mods. The shortened calipers are very handy for slipping into a pocket when off to do some shopping; especially since metric and inferial are just a button touch away. HF used to sell 3" cheapies. I have a pair and they are my shopping calipers as well as being very useful for in situ measurements when the mill spindle is down close to the workpiece.

Another handy caliper modification is to center drill two spots, one on each jaw, separated by a convenient distance, e.g. 0.2". Now, to set your dividers to a desired radius, stick the points into the spots and open the calipers until they read the radius minus the separation distance.

Also, novices should be aware that calipers are a good substitute for fine tweezers when needing to remove one of those annoying steel splinters from a finger.