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Best Mill DRO for the money

jraksdhs

Aluminum
Joined
Jun 10, 2014
Location
Dover, DE USA
Im sure this topic has been beat to death here but being a new member I havent seen much about it lately. Ive done some searches but most of the threads are older. That being said, Im looking for a DRO that is a good quality and affordable. Somewhere from 500-700 bucks, maybe more if its the right system. Its will be for a 9x49 mill and I think I only need a 2 axis system. Im not looking for a ton of bells and whistles but quality and accuracy is needed. If there are recent threads discussing this I'll be happy to read those if you post them here. Thanks.

Jason
 
I think you'd be doing yourself a disservice if you didn't get three (if not four) axis readouts. I have X, Y and the quill Z on mine and wouldn't be without it.

Sorry but I have no recommendation other than that the very old Mitutoyo I have on my lathe still works after at least 30 years. On my Alliant milling machine it's a Prototrak control with glass scale position readout so not an independent maker of DRO.
 
I think you'd be doing yourself a disservice if you didn't get three (if not four) axis readouts. I have X, Y and the quill Z on mine and wouldn't be without it.

Sorry but I have no recommendation other than that the very old Mitutoyo I have on my lathe still works after at least 30 years. On my Alliant milling machine it's a Prototrak control with glass scale position readout so not an independent maker of DRO.

Dunno if it works out cheaper or not, but instead of a 3 axis scale on our bridgeports we have x and y, and then one of these for the quill. It's not a true Z axis scale, but for the work we do on a BP, it works fine.
 
Sorry I did not cheap out on a DRO.
A good one that has lasted me over a decade and I have never turned it off has been a Newell.It is about 2X your budget though,and it has bells and whistles.I would buy again if needed.
 
i have an anilam 211 2 axis wizard on my mill ($500 used), and a $25 digital caliper style scale on the quill . i wouldn't bother with the knee , as there's never going to be any play in the elevation screw with 700# of knee and table on it. it's at least 25 years old - i've had it for 10 .
works like a champ.

these look promising: DRO 2 Axis Mill Bridgeport Package Linear Glass Scales New Free Shipping | eBay

and ship from illinois - so there should be english speaking support if there were any fuckups .
 
I've got my fingers crossed about the 4 axis magnetic scale kit I bought from Dropros. Supposed to read out to 2 tenths, be impervious to contaminants, and the scales and read head are much smaller than the typical glass scales. Quite a bit over your budget at 1500, but I don't think you've set a realistic price point for quality.
 
ive heard that magnetic is better than glass. Any truth to this? DRO pros has a 3 axis package for 1100. That seems like a good deal, considering its only a couple hundred bucks more for a 3 axis. Does anyone have the EL400 head? And how is the install?
 
Jenix ones have worked well for me. Like $550-650 bucks for a X,Y,Z,Quill for my Lagun. Near the same for my 15x40 lathe. Made in Korea and warranted for 6 years. Glass scale type with the standard .0002 resolution (except on lathe crosslides where it is .00005).

Jenix dro
 
Sorry I did not cheap out on a DRO.
A good one that has lasted me over a decade and I have never turned it off has been a Newell.It is about 2X your budget though,and it has bells and whistles.I would buy again if needed.


Another vote for the newall here. Saves setup time when doing one off hole patterns.
 
ive heard that magnetic is better than glass. Any truth to this? DRO pros has a 3 axis package for 1100. That seems like a good deal, considering its only a couple hundred bucks more for a 3 axis. Does anyone have the EL400 head? And how is the install?

I'll have more to report soon. I have the DRO, now I'm just waiting on the mill. Cart before the horse, I suppose, but I was SUPPOSED to have the mill last month...
 
From a install and durability standpoint I must admit I love the Newalls. Just the price can be a bit much at times. I was looking at one that would fit my No.4 horizontal mill and it was nearly double what I paid for the whole mill with tooling. Not exactly cost effective until I can line up some horizontal mill only jobs to justify the expense.

Then again my No.4 was used by a mold maker for 30 years without a DRO and his opinion was you can do just fine without them, he did, and was busy until the day he retired. For me, I have just gotten so spoiled by them I can't imagine not having one. Going to see how it goes in use, needing an X axis scale that would be the length of a Z axis one off a lathe is really driving the cost up.
 
I have a Electronicia 3 axis from DRO Pros on my new Webb Mill and it works great. I have 2 other Sargon DRO's on my Excello and lathe and they haven't been turned off in about 15-20 years and work great also. For the money and features I would buy from DRO Pros again without question.
 
ive heard that magnetic is better than glass. Any truth to this? DRO pros has a 3 axis package for 1100. That seems like a good deal, considering its only a couple hundred bucks more for a 3 axis. Does anyone have the EL400 head? And how is the install?

A few years ago I purchased the EL400 2 axis kit for an older Bridgeport. I like the readout and the magnetic scales. The kit was easy to install and does read down to .0002 as advertised. The mill gets used about 20 hours a week so it isn't exactly a production machine. The only drawback according to DRO Pros is that you is that you shouldn't use strong magnets in close proximity to the magnetic scales. I've used magnetic indicators regularly on the table with no ill effects.

I chose the 2 axis model because that's what I'm used to. I didn't see a need for a scale or readout on the Z axis. At work we used Accutite, Analam and Newell DRO's. They all worked well, but were dated when I started there nearly 30 years ago. I'm sure they're still good, but a little out of my price range.
 
In March 2012 I installed a 4-axis Electronica DRO with 0.0002" scales I purchased from DROPros. However, had I known then what I know now I probably would not have purchased it. The sales people at DROPros are great, the price is low, and the unit is easy to use, but my measurements have found an issue with the stability of the material used for the scales.

Making a long story short, a week or two after receiving the DRO in March 2012 I finished installing it. On a day when everything had sat for at least 8 hours at 20 oC, and when zeroed with respect to the mill's dial at one end of the travel, it read low by 0.0010-0.0016" at the other end of the full 24" travel. This is consistent with "perfect" DRO scales and a perfect-when-new lead screw on the mill that has ~0.002" of backlash at one end of the travel. Since this was good enough for my purposes, and since it was within the claimed specs of the DRO as well as the accuracy of the test I did, I did not try to check it better than that at that time

Twenty months later, in December 2013, and with everything equilibrated at 15 oC, I rechecked the scales using a centering microscope and the scales on the side of 18" Mitutoyo vernier calipers (which are spec'd to be accurate to +/-0.002"). To my surprise I found the DRO readout to be low by ~0.014" at full travel, i.e. well outside the specs of the calipers and 10x worse than when new 20 months earlier, and well outside the claimed specs of the DRO. I rechecked this using 25" B&S vernier calipers and got the same result so I used the deviation I found to input a linear deviation factor into the DRO's readout. Note this new "calibration" was only done using vernier calipers, and I didn't know whether or not the deviation actually was linear, i.e. if the scales had uniformly expanded over their entire length, or if the expansion was different in different regions, so everything would have to be checked more carefully.

Because of what I had found a few weeks earlier, in January 2014 I used my recently calibrated grade 2 Mitutoyo gage block set to check the scales again. This time at 20 oC I found the DRO readout was within no worse than +0.0004" over any 9" length of the full 24" travel. That is, with the new calibration constant I had entered a few weeks earlier, which was significantly different than the one it came from the factory with almost two years earlier, the DRO was working well enough for my purposes.

However, even though things were fine in January, this does not mean the scales won't continue to change their length in the future as whatever stainless steel alloy the factory used continues to age. So, during this period a third party put me in contact with an engineer at the Electronica factory in India (it only would have made matters more complex to try to deal indirectly with them through DROPros, which is only a sales outlet for them). In our initial exchanges the Electronica engineer was quite responsive. However, he went completely quiet after I provided him with information to indicate I have the expertise and instrumentation to be quite confident my measurements are correct. I have no idea why he went quiet because he stopped responding without providing any explanation.

It appears to me from my measurements that there is a fundamental problem with the temporal stability of the material they use for their scales. Whether this could be solved by them finding an accelerated aging process for the steel, or letting it sit for a few years before they apply the magnetic scales and calibrate it, only could be addressed by long-term measurements to determine when the aging has slowed down sufficiently so as not to be an issue.

Meanwhile, I basically have two data points on how the scales change their length with time. When new (presumably within a few months of manufacture) the fairly crude check I made at that time found them to be within a few thousandths of whatever length they had when calibrated at the factory. Twenty-two months later they had increased their length by ~580 ppm from the value they had when calibrated at the factory. This corresponds to a position error of ~0.006" out of 10", which certainly isn't negligible for many things made on a mill.

When winter comes and I again can make measurements at 20 oC I certainly will. My hope is that I will find the changes have slowed down. At this point, at least, returning the unit and starting all over again isn't something I want to contemplate. Meanwhile, these changes are a headache I will have to live with, that I wouldn't have to live with had I purchased a unit with glass scales.
 
As a result of writing the previous post I couldn't stop myself from making another measurement. However, because of unknown (but small) differential thermal contraction, the following doesn't count as an actual "calibration."

The mill has been at 27-28 oC for the past 24 hours. Since as described in my previous post the scales on my 18" Mitutoyo's vernier calipers (at 15 oC) agreed with the gage blocks (at 20 oC) to within better than 0.001" over their length, and since using them is a lot quicker than setting up the gage blocks, that's what I used just now. At 18" I found the DRO's readout to be 0.0026" - 0.0030" low, consistent with continued aging.

Two big 'Ifs" follow: if the thermal expansion of the Electronica scales and the Mitutoyo caliper are identical, and if I linearly extrapolate this additional 0.0026-0.003" expansion since January (i.e. 6 months) to 22 months, it predicts a total expansion of 0.013"-0.015" over the same length of time I previously found it had been ~0.014". That is, from today's measurement it appears the aging/expansion of my mill's Electronica scales is continuing at the same rate as before. If this turns out to be the case, in another 16 months it will mean that had I simply left the factory calibration in place, after 44 months it would have been off by ~0.012" out of 10", which would be an accuracy 60x worse than its 0.0002" resolution. If nothing else, this Electronica DRO nicely illustrates the practical difference between accuracy and resolution...
 
i wouldn't bother with the knee , as there's never going to be any play in the elevation screw with 700# of knee and table on it.
A mill functions every bit as well without a DRO as with one. For the operator, on the other hand, a DRO makes everything faster, easier, and much less prone to error. While I agree you don't need a 4-axis DRO, I find having the DRO keep track of what I do is way better than trying to keep track myself. Whether I move the quill or the knee (or both), my DRO tells me how deep the cutter is into the piece. Again, I don't need it, but I certainly wouldn't like to do without it.
 

Your findings trouble me greatly. Can I assume you have checked to see if the clearance between the scale and the read head is still the correct distance and not increased by way wear, and also that the orientation of the scales are still square to the read head?

I don't assume to be smarter than you by any means, but if I just spent $1500 on a polished turd, well, that would be enough to upset a fellow...
 








 
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