[Tom Goldman]

Like Alan said the spring is the most important thing....without it consistant readings are impossible.
Some indicators have a external cap that can have a stiffer spring installed.
I prefer to use a point tip micrometer for rod bolts.
Altho it takes a little more time, the micrometer is more durable,and repeatable than the indicator...Most people just dont like having to read tenth's on a mic.,but I feel more comfortable with it than the dial.
You tend to develop a feel for a given bolts yeild relative to the ammount of pull and rotation you exert.