No, the machine will still move, spring, etc. , less so with a new machine; even using CNC programming, the machine will spring. Knowing how to mill with repeatable light cuts will eliminate this, and this can be allowed in the programming or freehand.
If working really tight, production shop, I know a shop that makes parts for Bendix who sub-contracts to the Air Force; these guys lease a new machine for a year, then get rid of it and get a new one---CNC multi-axis in 6 decimal point tolerances. But they still do the bench work.
For fun, rig up a good quality, ground dowel pin, in the vertical, in a vise or however, a quality v-block and use a good quality dial test indicator like BesTest graduated in .0001" . Repeatably coming in to the dowel pin in X and Y using the DRO, mind you, taking out the slack by winding the hand screw back 2 turns and back in and using the same zero point on the dial indicator. Do you get repeatable results?
Now, go do same with a Moore! Well, that is not likely you will find a Moore.
DRO has its advantages, but it just gets you close, depending how tight you are working and how critical the hole centers need to be. Best way is do your 1st hole, then the next hole, measure and adjust accordingly.
Moore was making their leadscrews in millionths of an inch tolerancing in the 1950's and easily making dependable .00005" inch moves and without DRO. It is interesting how situating the motor, its heat will throw off the accuracy of doing the work, when working tight.
But you know what? You guys are mostly hobbyists. The only person you have to answer to is yourself.
My 1st year at apprenticing was learning how to use a file, stones and crocus cloth, hand tapping, etc. and most all of it was bench work, not machine work. Oh, yeah, don't forget using the lapping table and lapping in holes using various Clover compound grits. Actually, silly as it is, my 1st few days was handling a broom. A lot can be learned by the instructor's student as how he handles a broom.
That 1st tool room shop, we layed everything out in Dykem blue before moving to the mill. I do same in my home shop with my granite surface plate and height gage. I do this primarily as to checking myself as I go. And I can surprisingly easily mill freehand to .030" . I don't have a DRO, I use an aluminum metric/inch yardstick on my lathe and dial indicators if I need to be fussy.
For the mill, I might get a DRO. Acu-Rite is the best I have used in the shops, but I have been away from it awhile. My cellar shop is damp and not very kind to anything electronic.
Kurt
=================
re:
--- In GrizHFMinimill@yahoogroups.com, "dave_mucha" <dave_mucha@...> wrote:
>
> I have to totally disagree.
>
> the DRO allows you to get close, fast. you do not have to count handle turns, just watch the numbers rolling by.
>
> a 1/4" 2 flute end mill OD is not the same OD, nor will it cut the same slot as a 4 flute.
>
> with indexable inserts, the radius has to be allowed for. as does tip wear, and machine play and machine/part/tool temperature.
>
> you rough in with the DRO, you finish with the mic's.
>
> using a DRO with 0.005" readout would speed up most work by orders of magnitude. the skill is in the finish and that is operator ability.
>
> IMHO, the DRO is a simple tool. it can be calibrated to achieve superior accuracy, but at some point it will be more accurate than the machine. and if the machine goes from one end of it's play, to the other, it could easily be a couple thou. the DRO would never know it.
>
> Dave
>
>
>
> >
> > The reason for DROs is so that you can make accurate stuff *without*
> > measuring with mics, and so that bend, springback, slop, mounts, screws
> > and bearing errors are eliminated.
> > DROs are really good and useful, precisely because they allow one to
> > actually get to 0.01 mm accuracies, easily, fast, and without measuring
> > with mics.
> >
>
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