Originally Posted by BigFish
That's a depth micrometer. Commonly used by master "techs" to measure the tread depth on front caster wheel tires!
You can also use it to check the combustion chamber depth...
I got it when I was having trouble with machine shops shaving too much off Kohler heads.
The valves like to stay open when you shave them too much..
Shimming the rockers is the only way I have found to overcome that problem.
Doing all the valve and headwork myself was how I eliminated the problem.