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Uman
10-18-2003, 10:52 AM
The Mitutoyo Digimatic DRO is for sale at Penn Tools for $525. I will be installing it on a 12 x 36 lathe. The specs for this DRO imply it is for a mill. Will this DRO work on a lathe and is it any good?
Jeff in Florida

SGW
10-18-2003, 11:05 AM
How much accuracy do you need? The Digimatics have an accuracy of about +/- 0.001" over a short distance, I think, maybe +/- 0.002" over a long distance. Check the specs, although they may be hard to pin down. Note that "resolution" is not equivalent to "accuracy."

IMO, it will be fine for the carriage travel. For the cross slide travel, I think you'll find the accuracy seriously inadequate if you try to rely on it exclusively...but even if you have to measure the last thou by hand, being able to use the DRO to get within a thou or two of final diameter will be a big help, anyway.

debequem
10-18-2003, 01:40 PM
For the lathe you need one axis that is twice as high a resolution as the other.

That is, when you cut the diameter, each 0.001" that the slide moves in will take 0.002" off of the diameter of the work. To accurately resolve the diameter of your work to 0.001" you need a scale with a resolution of 0.0005".

Now precision is another matter. Precision is the ability to perform the same measurement multiple times with the same results +/- the precision of the measurement tool. I think the precision of the Digimatic is +/- 0.001". that is a tolerance of 0.002" linear. That translates to 0.004" tolerance on your diameter of work. Not very exciting.

This is probably why DROs for lathes cost more. they need a higher resolution in the one axis than found in the X/Y for mills.

Since the accuracy of the Digimatic is a little on the low side, it may not satisfy your needs for precision measurement of diameter.

Marv

[This message has been edited by debequem (edited 10-18-2003).]