DROs from China: Quality, Reliability and Accuracy? Any USA made DROs?

Ok.
I'm sure this must have been hashed over before. I've read some reviews/ratings where people are finding some China manufactured DROs to actually be decent quality and reliable, but I figure this crowd is more informed and harder to impress than the reviews on Amazon and eBay.

Anybody have one of these or similar:
2 Axis Digital Readout Dro for Milling Lathe Machine with Precision Linear Scale by Taishi: Amazon.com: Industrial & Scientific

They come with 5 micron scales, but they claim for a $20 upcharge, you will get 1 micron or 0.5 micron scales... Really?!?? Are they actually accurate?

Are there USA made DROs? I'm definitely willing to pay more for accuracy/quality/reliability.


Recommendations for reasonably priced lathe DROs that provide 0.0002" or better resolution?

"0.0002" or better resolution?"

while you can resolve to a kabillionth of an inch or mm.

what machine do you have that is more accurate than .0002 ?

why would you expect a $200 dro to be so good.

just sayin...


i'd get a chinese one that's assembled here someplace , and offers a warranty.

good luck.

I have a SINO DRO on my unmentionable lathe. It's been on there for close to ten years with no problems. As to accuracy, I can't say, except it's got to be better than the lathe.

My Mill has a 2 axis Mitutoyo DRO that does the job, but it's not much different than the SINO.

Thanks for the response.

tnmgcarbide said:

"0.0002" or better resolution?"

while you can resolve to a kabillionth of an inch or mm.
what machine do you have that is more accurate than .0002 ?
why would you expect a $200 dro to be so good.

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Well, I kind of don't expect them to be so good, so that's why I'm asking how good they actually are.
I don't think any of my machines are that accurate (although my Hardinge is probably close), sometimes I do optical testing where having very fine resolution would be useful.
I have an AcuRite DRO on my Hardinge with 5 micron scales and I like it, but I have another lathe coming in sans DRO.

tnmgcarbide said:

i'd get a chinese one that's assembled here someplace , and offers a warranty.
good luck.

Click to expand...

I guess I just assumed they were all made and assembled in China.

I just recently purchased a Tpac 2axis DRO thst seems to work perfect so far. It was just under $400 for the readout and the scales

Many years ago I, along with several other members here bought a Meister Top 10 3 axis for a Bridgeport that has been going strong for about 14 years I think. It was $480 shipped way back then.

I bought 3 similar units (to your link) about 1.5 years ago. One 3-axis and two 2-axis sets (from a different vendor than your link).
I learned a lesson on the first unit purchased, I needed to specify that the readout be in ENGLISH! It was a PITA but the vendor helped me through the setup screens and it's fine. I was so impressed with it that I bought the next two from him as well (with english screens of course).

About a year ago the vise handle fell off the mill table and hit the cable to the Z axis knee scale on the new 3 axis unit and the scale was trashed. That's when I discovered that individual replacement scales on Ebay cost about as much as the whole setup. So I sent an email to the vendor I bought the sets from and explained that I just needed one replacement scale and he had one drop shipped to me for $100 ($60~$80 cheaper than Ebay at the time).

They are a great deal if cost is the main concern but you need to be handy with setup and troubleshooting. The manuals are total crap and if it weren't for the pictures on the pages would be useless to most. The manual I received with the original Top 10 unit was great and I was able to use it for the new units if for nothing but a guide to what the pictures in the new manuals were referring to.

Yes.
Stuff that is assembled here tends to be more detailed and fitted than what they throw into the container from the factory.

Maybe the difference between sharp/alliant and
Jet/grizzly.
The details make the difference.

I’ve installed two of the DRO Pros glass scale DRO systems on the machines in the robotics shop at the high school (I volunteer at the shop when I can). They’re fine. The bracketry is a little crude, but I roll my own. The lathe cross slide readout has too many zeroes but there’s no in-between setting between too much and too little resolution. The last digit jitters, but it’s sub-tenths. A piece of black tape would fix it!

Unlike some of the reports above, the installation instructions are really good, in real English, and aimed at the home shop noob.


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I am sure you wanted to make a point with "...the difference between sharp/alliant and
Jet/grizzly", but it is totally lost on me. And likely on the OP also.

I know that Jet and Grizzly are not made in the US, but frankly I have zero knowledge on Sharp or Alliant. Are they US manufacture? Somehow I doubt it. I wouldn't be surprised if they come from the same Chinese factories as Jet and Grizzly. I looked up a couple of models of those brands and they appear to be quite similar to Grizzly models AT FIRST GLANCE. I did not attempt to make a point by point comparison. But that is not the idea, anyway. The question here is the level of quality and that can not be determined from a sales description.

And no one talks a lot about the DROs that come as OEM equipment on their machines. There has been talk here about the RESOLUTION of the scales, but that is not their ACCURACY. A scale with 1 micron resolution can be off by a full millimeter in a meter and that would not be very accurate. When you compare DRO scales you need to think about things like the accuracy over the full length of the scale, about the linearity at various parts of that scale and other factors that are more important than the resolution of the scales. What difference does it make if you can read the difference between 500 mm and 500.001mm if both figures are off by 0.1mm anyway? And then if you move to 505mm and find that it is off by 0.2mm in the OTHER direction.

The resolution of a scale should be the last spec that you look at. IMHO, anyway. But it is going to be the first one that they brag about.

I suspect that the biggest factor between imported brands is the level of QC that the importer exercises when they order and accept the machines from the Chinese factories.

tnmgcarbide said:

Yes.
Stuff that is assembled here tends to be more detailed and fitted than what they throw into the container from the factory.

Maybe the difference between sharp/alliant and
Jet/grizzly.
The details make the difference.

Click to expand...

EPAIII said:

I am sure you wanted to make a point with "...the difference between sharp/alliant and
Jet/grizzly", but it is totally lost on me. And likely on the OP also.

Click to expand...

Sharps and Alliants have historically been made in Taiwan and have often been of good quality.
I have a Sharp HCV and it is a really nice mill.
I don’t have much experience with Jet or Grizzly mills, so I can’t comment on those.

Anybody have opinions on Supermax? I saw a pretty nice one for sale...

EPAIII said:

When you compare DRO scales you need to think about things like the accuracy over the full length of the scale, about the linearity at various parts of that scale and other factors that are more important than the resolution of the scales. What difference does it make if you can read the difference between 500 mm and 500.001mm if both figures are off by 0.1mm anyway? And then if you move to 505mm and find that it is off by 0.2mm in the OTHER direction.

The resolution of a scale should be the last spec that you look at. IMHO, anyway. But it is going to be the first one that they brag about.

I suspect that the biggest factor between imported brands is the level of QC that the importer exercises when they order and accept the machines from the Chinese factories.

Click to expand...

I agree for the most part that accuracy is more important than resolution.
However, unless a scale is grossly inaccurate, meaning you’d be scratching your head saying “WTF?!??”, in most cases, it is likely have some some degree of “local” accuracy. Most work is likely to be small, relative positioning versus the full stroke of the scale/axis/machine.

That said, I am most definitely concerned with accuracy and resolution that’s why they’re in the thread title :-)

SINO is the largest DRO manufacturer in China and their DROs are sold under many brand names. I believe the DRO Pro models are also SINO manufactured. As far as the other brands mentioned, they may also be made by SINO. If they look the same, they are most likely made by the same company. As others have stated resolution and accuracy are not the same. It is easy to have one without the other. As far as SINO DROs are concerned, I've had a 3 axis unit on my BP clone for 12 years. It has been flawless and it is accurate.

I know that Jet and Grizzly are not made in the US, but frankly I have zero knowledge on Sharp or Alliant. Are they US manufacture? Somehow I doubt it. I wouldn't be surprised if they come from the same Chinese factories as Jet ...

how many us made manual mills are made in usa? wells index. not sure where bpt
is actually cast, but QC is QC. plenty of fine machines from taiwan and korea.

I have both a Mityou KM (circa £500 last time i looked) and scales on the mill and a SINO on the lathe (sub £200), if either dies they will be replaced with another Sino, Brand wise, im not convinced you get much more for multiple times the cost.

IE IMHO and also born out through my experience, the sino are more than good enough, the so called better brands are in some ways just a larger hole in your pocket for little net benefits. Glass scales and the tech to read them is pretty standardised, how there made is intrinsically accurate so IMHO its not like spending more buys you all that much superior products or tech. If anything one of the key things you will find in threads on here over the years is the more oddball "professional - HIGH grade" ones people oftern have difficulty finding replacement scales and parts for. The Chinese ones have remained a lot more standard and far more maintainable from that point of view so far. Glass scales are some what delicate things and something hitting em hard enough will do them in.

If you want true real world micron resolution, then in any scale system, your into filling in and calibration to get there, both my Mityou and SINO have the option of error correction, for what i do single thou resolution works just fine and i have never found any error in either of them.

better DRO have a calibration mode you use a gage block and indicator and move a distance like 6.0000 and see what DRO says and if it says 5.9990 you press button and then when you go 6.0000 it will read 6.0000
.
you check each axis and calibrate. i have done before critical jobs many a time

DMF_TomB said:

better DRO have a calibration mode you use a gage block and indicator and move a distance like 6.0000 and see what DRO says and if it says 5.9990 you press button and then when you go 6.0000 it will read 6.0000
.
you check each axis and calibrate. i have done before critical jobs many a time

Click to expand...

Yep.
My AcuRite has a scaling factor you can adjust.
I’ll do some digging about Sino and the others to see what they have.

A friend of mine went with IGAGING and he's happy. They ship as a complete kit so you don't have to go hunting for extra bits and pieces. I'm tempted to put one on the lathe's tailstock. Tiny numbers are getting harder and harder to read.

I'm not sure if many realize the precision required for a good cross slide scale to be useful. You need .00005" resolution to detect .0001" on the diameter. And you need to be that accurate to be good to .0002" generally, because if the digits aren't changing, then you don't know what is happening to the tool position until such time as the tenths digit does change.

For Z scales on a lathe, well, I don't have any and seldom ever require high precision between multiple features (shoulder locations), so I make do with calipers and what have you. For the most part, Z length features are located relative to one another after a part flip, so you've got to relocate the Z datum. Hence the precision of a Z scale isn't useful until after a trial cut and a measurement with a micrometer or caliper. By that time, you're generally able to make tiny adjustments with the compound to achieve finish length. So you might save a few bucks buying a low precision scale for the Z axis if you need it.

gsg9.ca said:

A friend of mine went with IGAGING and he's happy. They ship as a complete kit so you don't have to go hunting for extra bits and pieces. I'm tempted to put one on the lathe's tailstock. Tiny numbers are getting harder and harder to read.

Click to expand...

Regardless of make and scale accuracy, I find the whole tribe of the greyish LCD displays Igaging use even harder to read.

If wishes were fishes, I'd want the Old Skewl blue-green vacuum/plasma displays Commodore popularized on the first sub-$200 desk calculators and top-end goods makers STILL use for lower delay or risk of reading error.

No such thing as a "perfect" display for all potential shop lighting conditions and angles, but those are close.

Tied for second place, those that use a general-purpose display, computer-screen style. or the lighted-up red, orange, or yellow flat-segment units.

2CW

rpseguin said:

Yep.
My AcuRite has a scaling factor you can adjust.
I’ll do some digging about Sino and the others to see what they have.

Click to expand...

.
had a lathe dro the calibrated mode a light would blink showing its on. if you pressed wrong button it would turn off and in uncalibrated mode it was inaccurate
.
strangest DRO i ever worked with. button not labeled very good and no description on DRO what blinking light meant. when i checked calibration and found off i found manual on the internet and read how to calibrate. like many things if you dont have the manual on it its almost impossible to figure out
.
i cannot tell you how many times i found somebody else trying to zero DRO turned the calibrated mode off. worse design i ever saw making it so easy to turn calibrated mode off

a precise glass scale w/ laser etching to .000000005 is lovely, but if the iron disagrees.... then its fuckall.
all the temp and humidity comp and curvature of the earth won't reflect environmental variance.