Re: [CAD_CAM_EDM_DRO] Fixing indicators

Joe Vicars wrote:

> Is there a good Internet "How To" for repair and maintenance of
> dial and test indicators? I have some that need fixing, I don't want to
> buy a book.

These things are actually VERY simple. Dial indicators have a plunger
with a rack on it, and a couple gears that drive the indicator hand.
There is a spring to preload the gear train against one side of the
backlash. There is a plain compression spring on the plunger.

Dial test indicators are quite similar, except that most use a sector
gear and a rocking mechanism to get bidirectional indication.
Again, a very simple mechanism. Access to the works is usually
through the back.

Generally, the problem is that the oil has gummed up. I don't know
what oil is best, I would assume that sold for watches and clocks
would be best.

I have just carefully opened up a few of them and found them easy to
get unstuck and repair. If you take them completely apart, there may
be some adjustment of the 'clock works' to get the most accurate
engagement of those gears to the rack or sector gear.

Jon