Choosing a glass scale brand that's "good enough"

[jrgilman95]

I'll start this off with that I'm pretty new the machining, and I'm not at a level where I think the scale will be my limiting factor - but also I don't want to install some garbage and have to replace it later.

I've been doing (too much!) research on this, and at this point I'm starting to go into a bit of information overload.

I was originally planning on getting ToAuto 1um scales, but at this point I'm not sure anywhere. There's people who say they're good and then there's others arguing they're absolute junk (including other Chinese brands that I've heard decent things about, such as Ditron). It seems like the main issue people mention is not the resolution but the accuracy over distance.

Just curious what people's experience is with various scale manufacturers - and honestly just looking for advice so I can get over the information overload hump.

 

[SouthernChap]

I guess there may be some people who disagree with what Yuri says , but I doubt those people have the broad experience that he has.

Here's what he says: https://www.touchdro.com/resources/getting-started/dro-scale-selection-guide.html

and here: https://www.touchdro.com/resources/getting-started/recommended-dro-scales.html

 

[Eddyde]

I bought my mill DRO off Aliexpress about 8 years ago. Eason brand, 1um, I paid just under $500 all in, with shipping for a 3 axis set up. It has preformed flawlessly and is very accurate.

 

[ycroosh]

I'll start this off with that I'm pretty new the machining, and I'm not at a level where I think the scale will be my limiting factor - but also I don't want to install some garbage and have to replace it later.

I've been doing (too much!) research on this, and at this point I'm starting to go into a bit of information overload.

I was originally planning on getting ToAuto 1um scales, but at this point I'm not sure anywhere. There's people who say they're good and then there's others arguing they're absolute junk (including other Chinese brands that I've heard decent things about, such as Ditron). It seems like the main issue people mention is not the resolution but the accuracy over distance.

Just curious what people's experience is with various scale manufacturers - and honestly just looking for advice so I can get over the information overload hump.

SouthernChap beat me to it. The Recommended Scales and Touch Probes is up to date and is based on a bunch of my testing and feedback from other TouchDRO users. There is also a sticky on the top of this forum.

Short version -

• Unless you absolutely must, don't use magnetic scales. Accuracy per dollar is much worse than glass scales.
• For glass scales: Ditron/Aikron/Sino are basically the same scales, as long as you get them for the official distributors.. There is a TON of fakes and factory rejects floating around. "Cheaper" stuff is cheaper because of lack of QA (or it's just straight QA reject from the decent brands). 90% of the time this means that you can get a dead scale; 10% of the time the encoder strip will be damaged/scratched and the scale will have a dead spot. You can't get an "inaccurate" glass scale (at least to the extent that you can measure without 50K$ worth of equipment).
• For magnetic scales: the best you can get for under $1000/scale is about +/-10um error over 1m (this includes Electronica/EMS, RLS, NeWall, and Mitutoyo). Stuff that you can buy for $200/scale will be much worse than this. 5um Chinese magnetic scales are universally complete crap; 1um scales are a bit better, but don't expect better than +/-10 um over 2mm (due to cyclic error) if you get super lucky.
• If you absolutely must use magnetic scales (and care about accuracy), get Electronica/EMS full size scale (S2/Magna). If you absolutely must have a slim scale, get RLS LM10 or LM13.

Hope this helps
Yuriy

P.S. Before I get a flood of PMs telling me that "my magnetic scales are perfectly fine" - don't bother, please. I don't have a dog in this fight (I don't sell scales, and don't get any kickbacks from any manufacturers), so I don't really care. And, I actually tested a bunch with a proper laser interferometer that can resolve down to double digit nanometers. None of the magnetic scales that I tested performed better than +/-10um that is stated in their spec sheets, and EVERY Chinese magnetic scale performed worse.

 

[ycroosh]

I bought my mill DRO off Aliexpress about 8 years ago. Eason brand, 1um, I paid just under $500 all in, with shipping for a 3 axis set up. It has preformed flawlessly and is very accurate.

Easson is unfortunately out of business, since their owner/founder passed away a few years ago, but their scales were top notch. Easson and Ditron were the two original brands that started making affordable glass scales (those of us old enough can remember the time when "affordable" meant "less than $1000 per scale" )

 

[jrgilman95]

For glass scales: Ditron/Aikron/Sino are basically the same scales, as long as you get them for the official distributors.. There is a TON of fakes and factory rejects floating around. "Cheaper" stuff is cheaper because of lack of QA (or it's just straight QA reject from the decent brands). 90% of the time this means that you can get a dead scale; 10% of the time the encoder strip will be damaged/scratched and the scale will have a dead spot. You can't get an "inaccurate" glass scale (at least to the extent that you can measure without 50K$ worth of equipment).

I really appreciate the response, I saw the glass vs magnetic post on your website (I definitely am going with glass), but didn't see the one where you stack up the brands (Thanks SouthernChap). Based on that list definitely going to go with Sino or Ditron. Likely Ditron via their eBay store that you linked. The prices are somewhat lower.

I messaged them already, but I figure it doesn't hurt to ask on here. For the BP quill, I wasn't sure if I should go for the exactly 5" slim scale or if I should oversize it and then cut it down (assuming that's possible). I also am not sure if slim is totally necessary - but it seemed that it would be good in that area since there isn't a lot of room to work with... Was going to get standard sized ones for the XYZ otherwise.

 

[ycroosh]

I really appreciate the response, I saw the glass vs magnetic post on your website (I definitely am going with glass), but didn't see the one where you stack up the brands (Thanks SouthernChap). Based on that list definitely going to go with Sino or Ditron. Likely Ditron via their eBay store that you linked. The prices are somewhat lower.

I messaged them already, but I figure it doesn't hurt to ask on here. For the BP quill, I wasn't sure if I should go for the exactly 5" slim scale or if I should oversize it and then cut it down (assuming that's possible). I also am not sure if slim is totally necessary - but it seemed that it would be good in that area since there isn't a lot of room to work with... Was going to get standard sized ones for the XYZ otherwise.

If you are planning to get a TouchDRO, I'd just get iGaging Absolute DRO scale for the Quill. It's going to be much less obtrusive and for the quill it's generally "good enough" (making a bold assumption here that you'd use the knee for precision stuff, and quill for drilling, etc. iGaging scales is good for +/- 10um in my experience. If you feel "fancy", Mitutoyo's quill kit is very good, but 5x more expensive and has a slower refresh rate. This is what I have on my mill, and I'm really happy with the setup (I started with all sorts of crazy plans, including an Acu-Rite SENC 50 (that I'm still living down... "You spent HOW MUCH on this thing that is now sitting in the drawer??????" )

Regards
Yuriy

 

[jrgilman95]

If you are planning to get a TouchDRO, I'd just get iGaging Absolute DRO scale for the Quill. It's going to be much less obtrusive and for the quill it's generally "good enough" (making a bold assumption here that you'd use the knee for precision stuff, and quill for drilling, etc. iGaging scales is good for +/- 10um in my experience.

I think the price is right here. I was curious about if their stuff actually uses the USB protocol or if they simply appropriated the mini usb connector for its size and are using something like UART or serial?

(I started with all sorts of crazy plans, including an Acu-Rite SENC 50 (that I'm still living down... "You spent HOW MUCH on this thing that is now sitting in the drawer??????" )

I definitely have never done this, ever. Nope