Installing a DRO

[aucran]

Hi,
I'm having trouble mounting a DRO and was wondering if anyone can give me any tips to get it running level.

Its two-axis using glass scales.

Right now, I have it mounted, set up and running, it just reads about 0.101" for every 0.100" turn of the handle. Not a big deal until I move over half an inch. :x

Are there any tips to getting a better tolerance out of it? I've spent a good amount of time figiting with the linear encoder and the scales to try and get them both level and parallel with each other.

I'm starting to seriously consider re-mounting both...

[TroyO]

Is it possible the DRO is right and the handle is wrong?

Maybe check it against a dial indicator and see which 2 agree?

[aucran]

Hi,
I tried what TroyO suggested, and measured the movement of the table against a dial indicator. (Set on the table surface pushing the flat surface on the quill.)

Using the dial to check how far I moved the wheel, then checking the hand wheel reading, I was impressed, the hand wheel marks seem to be spot on. My DRO is still off, about 0.0008" for every 0.100" movement.

Thank you tho TroyO, I'm glad to know I can use the mill readings accurate, I never checked those when I first got it.

I'll keep trying to shim it around until the DRO reads better. My goal is +/-0.0002". Which shouldn't be unreasonable for glass scales.

[TroyO]

I figured it was worth a shot... you didn't mention what mill, but I seemed to recall that some machines use metric screws but mark off in imperial, so the leadscrews are actually off a little. Although... I think that error was more like <.001 per inch, not per .1 inch.

[aucran]

I think its just the scale, I must have it mounted at a bit of an angle compared to the travel of the table, I'll drill some new holes this evening and see if I can do a better job.