# thinking about getting cheap dro for my mini mill



## MCRIPPPer (Jan 10, 2013)

hey there. im thinking about getting the igaging remote dro (basically digital caliper without jaws and a little box on a wire that houses the lcd display.) for my sieg sx2. i have the micro mark one with the 20tpi leadscrews. 

the dro im looking at has only 0.001in resolution (same as hand wheel lines) but they only have .002 in accuracy. do you guys think this will be a step up from the standard screw? i seem to have difficulties getting features exactly where i want on parts sometimes. thankfully i never need to go super accurate, but more is always better as far as accuracy. im just wondering if the feed screws are already more accurate than 2 thousandths. the dro would be nice for doing occasional metric work, and just make life easier. my little mill seems to have alot of "spring" in the controls, as in, it is hard to tell when the wheels actually move the table, or if it is still taking up slack and flex in the system. the z axis is especially bad with this issue because the power has to go through a shaft, then through a worm wheel, then to a gear, then through a castle nut, then through another shaft to another gear then to a gear rack and then through the screws that hold the gear rack on, and then the head finally moves lol. so if you can imagine, i turn the "fine tuning" wheel, and it gradually increases in tension until the head actually moves, and its hard to tell when that happens. i know for sure that even a 2 thou accurate scale will improve my z axis, but im not so sure about the x/ Y.


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## MCRIPPPer (Jan 10, 2013)

for pretty much the exact same price i can get digital calipers with higher accuracy, but no remote display. what is more important/ useful?


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## TDHofstetter (Feb 20, 2013)

Quick answer: "Depends".

If you use (liquid) coolant, you can expect some to get onto a non-remote caliper's display face & make it hard to read. Chips can get there, too, and you may have to clean it off often to be able to read it.

If you're not reaching for one-thou accuracy, don't worry about the less-accurate remote scales.

If your eyes aren't up to peering at a little display mounted next to your axes, you'll want the remote display... although I find it a little disconcerting to be looking at a display that's very far away from the work - it feels disconnected; I like to see the work instead of just watching numbers.

Another approach would be to add dial indicators on all three axes - some eyes like dials a lot better than digits because they give you a "sense of approach" you can't get from digits, and a dial indicator gives you one-thou precision or better... at the cost of limited travel - most dial indicators are only good for about 1" of travel. You can get around that in some cases, though, with a steel rule oil-stuck to one or more of your ways to serve as a coarse indication, using the dial for the last nadhair of travel.


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## eac67gt (Feb 20, 2013)

We have the same DROs on all three axis of our Little Machine Shop minimill and for most work it is fine. I agree about the "spring" in the controls but a lot of that can be taken out with some fine tuning or mods.
I have found the readouts to be very helpful but then I am fairly new to machining and have not experienced larger more expensive machines. The DROs in question are easy to mount and cost effective for the small hobbyist.
I just added a digital caliper to the minilathe on the compound. I hacked the jaws off a cheap digital caliper and mounted it and it works great. Got it on sale at Harbor Freight for $9. Couldn't go wrong. I saw someone else do this that is where I got the idea. 

Accurate hand calipers being it dial or digital is something you should always have though, it is an important, most have part of the machinist toolbox.

The bottom line to me is for a small mill like yours the igage DROs will be fine. That is my opinion though. :nuts:

Have a great day!

Ed


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## toolman49 (Feb 20, 2013)

Hi Fellas,
About a year ago I fitted a pair of scales to my RF31 (unbranded, appear to be OEM Igaging units) and have been completely happy with them, needed to add mini USB extension cables as the standard ones were a bit short, also ran cables through 10mm split conduit to protect them. The scales are mounted inside 50mm C section aluminium extrusion with plastic end caps to keep the crap off. The only irritation is the auto shutoff every 4 minutes, but it must work as I am still running the original no name Chinese batteries.Total cost of the project was about $Oz 100.
Regards,
Martin


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## rdhem2 (Feb 25, 2013)

SHARS has some pretty nice units for pretty nice prices.  They are great to deal with, great service, fast ship.  Little old lady there sounds like your grandma!  NEAT. Several sizes and options to choose from.  Check it out.       :sailor:


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## itsme_Bernie (Apr 3, 2013)

The Igaging Scales are on sale at Grizzly right now!!  I just bought a few! 


Bernie


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## bix (Apr 3, 2013)

I put three of these on my Grizzly G0704 (X, Y, and Head Z), three on my 7x12 mini lathe (Carriage, cross-slide and tailstock), and one on my drill press quill. I'm a big fan of these inexpensive readouts and think they are among the most useful improvements I've done to these tools.

Regarding the readouts: you really have to keep the slides as free of grit and fluids as you can - they do act up and get very erratic if they get dirty. They are particularly sensitive to steel grit. On the mill I put a cover on the X scale and on the lathe I put one on the carriage scale and will be modifying the cross-slide scale to also have a cover in the future. The covers have made a huge improvement.

When they do get munged up the behavior is very erratic. I've brought a couple back to life by disassembling the sensor that runs on the slide, carefully cleaning everything I could with alcohol, and then blowing it dry and blowing out anything else with compressed air.

On the mill, I've found I didn't really need the Z-axis readout on the head position on the column. This mill includes a digital readout on the quill, and so far that's the only z-axis reading I've needed.

The scale on my cross-slide is not the remote readout type, but has the readout right on the sensor slide. So it's a little different than the igaging remote readout. Having said that, I found there was just a little backlash in that DRO and I assume it would be there in the others as well. It was hard to actually find. I had converted the lead screw nut to an anti-backlash nut but I was still seeing about 0.001 of backlash. I tore my hair out trying to find the source, until I put a test indicator on the slide and found that in fact the slide did not have any measurable backlash, and that what I was seeing was the backlash of the digital scale. So if you care down to that level, then you should be aware and assume there is some very small backlash in these digital gauges.

FYI, the mill readout mod I did for the G0704 was pretty much one posted on MadModder: http://madmodder.net/index.php?topic=6512.0. I used the same design for the X slide cover on my lathe carriage DRO slide cover, which is on the back of the lathe.

bix


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