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Usage on Lathes


Dial indicators using a magnetic back (such as Starrett's No. 676 Series) can be very useful in setting up a job on a lathe where the machine's screws may be producing too much backlash. By using a indicator in a similar fashion to a Digital Read Out (DRO) one can still machine accurately and quickly on a machine they have not developed a feel for yet.




As you can see I set it up in 2 different locations, one that makes it relatively nice to thread as you maintain your cross slide zero as you move the compound in but continuously move the cross slide in and out as you move the cutting tool back to restart the thread. While the other picture shows the dial indicator controlling the length of cut. Remember when setting up for the length of cut, you can use your gage block set to build a stack so that your indicator is just set at reading for example .500 when the depth is reached, even if the cut length of for the job is actually 4 inches long.

Personally I use the Starrett back I mentioned above, with a cheap indicator. I couldn't let a decent (Starrett, Mitutoyo, Mercer etc) indicator get flood coolant or hot chips all over it. A cheap indicator makes a good disposable. And the Starrett back has not given up its magnetism like cheap magnets seem to do.

The way the Starrett back is produced, it doesn't effect the mechanism of the dial indicator due to its enclosed design on all the surfaces execpt for the one which is physically touching the metal object you wish to affix your indicator on.

Dimitrios Simitas

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