Do DRO scales have to be level?

Pcmaker

Pcmaker

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I just put in a 3 axis DRO on my mill and I just "eyed" the levelness of the scales. Do the scales have to be indicated to be perfectly level with the mill?

Also, it when I move the axis .009, the DRO sbows something like .0000952. The DRO manual is too confusing to read.
 
Make / model? Glass or magnetic scales? Copy or link to manual?

Ken
 
Never mind. I was doing it wrong.

The machine seems pretty accurate so far. I used an edge finder on a 3-2-1 block
 
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I wouldn't say perfect, but mine said within 0.005". Mine are glass scales. If they are too far out, they won't display movement at all. All the glass scale install documentation I've read says you want that spec in both directions. I indicate the outside of the body 90 and 180 degrees from the read head. Level (to gravity) is not relevant, but you do want them to be in line with the movement of the machine.

Being 10x off makes me wonder if the DRO head is set for the wrong type of scale. However, I did see a case where the reader was not able to detect movement if things were misaligned too much. It's possible yours is off enough to miss some of the counts, giving an invalid reading. Indicate it in and try again. If you still get weird results you may have to contact the seller. I've never used that model, so I can't help with details.

Are you really displaying 7 decimal digits? Mine only go to 5 and even that I turn down to 4.
 
I'm no DRO expert by any means, but some of the instructions I've seen do say "level". But my thoughts are along the same lines as Winegrower and it being perfectly parallel to the axis as the key factor. If your scales have the option to calibrate them, that may be worth looking into if they are still off. Many say they are "laser calibrated" at the factory etc, but that doesn't mean they are still so after a boat trip from China and countless train or truck rides.
 
In another lifetime I use to install DRO's for a living. The scales, regardless of type, have to as parallel as possible to the motion of the axis of which it is measuring. Typically I would pick a location and mark one mounting hole to be drilled and tapped. I'd hang the scale from that one hole and snug it up. Naturally that hole was as close to the center of the scale as I could get. I don't know about these import models that are prevalent today, but the industrial models, with the cover removed had an indicating surface that was parallel to the scale. I'd mount an indicator to the table to indicate that surface, move the axis and shoot for about 0.001 from end to end. Probably more critical than it needed to be, but that's what we were instructed to do from the factory. I think they figured if we shot for .001, then we'd be within .010 in the end. There was more than one time that I had to open up one of the mounting holes in the scale to make it work, but don't tell anyone. LOL
 
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