Need some milling machine info

[wrmiller]

Maybe so but it's a good one. How do you know your DRO is accurate? How many times do you check your DRO?

You have used the dials and know how to use them and for this reason you put your trust in the DRO. If you were never allowed to use the dials and only knew DRO methods you would be lost? Perception is what you know today or knew when you used the slide rule, but education changed this. Some opinions are misguided perceptions based on lack of education. Education is the force that constantly changes perceptions and opinions.

A piece of swarf on the dial isn't going to change the accuracy of x or y but the same isn't true if the swarf is on the scale of your DRO.

I used gauge blocks to test the accuracy of my magnetic scales after installation. I've never even looked at the dials on my 935 to be honest with you. And so far (knock on wood...) I've had zero issues with swarf.

I'm not going to trust the tolerance stackup of a stamped dial+shaft+nut+leadscrew interface to gauge absolute position or a translation along an axis. But that's just me. Without the DRO and scales, I've used dial indicators and other mechanical measurement methods to give some level of accuracy to my work. The scales also give me both absolute positional data from a measured/known reference as well as translation along a axis, without all the jury-rigging necessary to use other contrivances. Seems to have worked well so far for what I do.

True, I learned to machine counting dials, and you have a valid point about perceptions. But having used dials doesn't give me trust in my scales. Hardly. I don't trust anything, and measure to make sure. But, measurements are only as accurate as the device taking the measurement so that must be taken into account as well.

 

[mksj]

I am with Bill on this one, a DRO just makes life easier and I do not loose count of the turns. Still, when installing the DRO, you need to use the machine in manual mode to make parts. Just did this with my mill. A DRO scale does not loose accuracy, it may fail or loose a reference point, so nothing is 100%. But installed correctly, they sure make life easier, especially as your eyesight tends to go. I focus on what the machine is doing, and am thankful I do not need to read the dials (for the most part). I check the accuracy of the scales after the install, that it tracks against my dial gauge and 123 blocks so you know that the scale resolution is set correctly, that's it unless something isn't working out size wise. Do not think that the mechanical leadscrews and dials are the last word on accuracy either, my last mill would loose 0.0003" per revolution (0.1") because they used metric leadscrews with inch dials. This required a DRO, and that was the only thing I used for years with never a glitch. The other factor is that you can get a very decent DRO for much less than years past, something in the $300-600 range.

Lets say you want to drill 4 holes in some pattern with your mill, factor in the time it takes you to do the layout, set up your position and then figure out the travel increments on the dials. Then repeat the process with a DRO, touch off and zero you coordinates on the screen and then just use increment setting for hole to hole or layout the pattern on the DRO screen and you are off and running in under a minute. Maybe with a lot of time and practice I might get close to the DRO accuracy, but when I am line boring sequential holes that have to be within 0.001" it is much harder doing it with dials.

I would ask the post originator as to what are the problems he is having using the mill, and then we may be able to provide some more specific recommendations.