I already had a thousands of an inch Dial Indicator. What I did was opt to spend the extra Money and get a Metric Dial Indicator.
It cost about $10-$15 (meaning in the $27-$35 range + shipping if you order it) more to get one (I have not seen Metric Indicators for sale at Harbor Freight) but it does away with having to calculate or gestimate the measurement.
Mail Order machinist supply places like Enco and VME sell them.

Mainly having the metric one it is a convenience.

About 3 weeks ago I did buy a new Magnetic Base form Harbor Freight and it is better made than the made in Taiwan one I have used since the 1980s; The Harbor Freight one is much sturdier. It was on sale at that time at about $10.

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84 300D, 82 Volvo 244Gl Diesel