What are your thoughts on something like this?Depends on how much you want to spend, the cheaper magnetic scales/DRO's tend to be quite inaccurate despite the quoted resolution of the reader head. Lots of posts on problems with the Ditron magnetic scales, and probably applies to most of the generic. Glass scales use a grating system that in most cases is accurate despite the price range, but can suffer from poor lip seals and the data transmission from the head. Better magnetic scales from Electronica or SRA, hold their accuracy over distance. I use and EL700 with magnet scales on my mill and it has performed very well, other than not a big fan of a touch screen. Magnetic scales are smaller and less finicky to install in my experience. They are considered to be less prone to coolant damage, but can become erratic if a metallic chip gets between the reader and the tape. The better heads do have wipers on either side of the head. On the mill I like to use the graphical DRO heads with soft keys for different DRO functions. I also find them easier to read in different light conditions and some have summing of two axis. Also nice to have the feed rates displayed, etc. If you want just numbers and less expensive DRO I would go with glass scales. Quite a few people have bought the ES-12B with magnetic scales from Machine DRO in the UK, my understanding is that Easson may no longer be producing these DRO's, but they work very well (I use one on my lathe).
Ditron vs Sino...wich is better in your opinion
@ycroosh - Any thoughts on my Ditron read head with 6 wires? I do not see this variation listed on your website? Is it RS422 without reference? @WobblyHand ? With only 6 wires, I'd guess it was A+, A-, B+, B-, +5V, and GND. However, I'm not an expert at this at all.
Easson ES-12B LCD digital readout package including 3 linear magnetic encoders
3 Axis Easson ES-12B LCD graphic digital readout package with three magnetic encoders. The encoders offer a very compact profile size and can be cut to length to custom fit the machine being installed. The package is suitable for mills up to Bridgeport 42" sized machines or 30" between centre...www.machine-dro.co.uk
You can also sum the Z and U axis on these displays.
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Glass or Magnetic?
- Thread starter Arcstar*
- Start date
That unit is a Ditron, the accuracy (not resolution) is something like +/- 0.002"over 1" which is quite unacceptable. The only magnetic scales I would recommend are those from DRO Pros who sell the Electronica line and those from the Machine DRO in the UK (SRA in the US), and then the high end ones like Newall, etc. which get very expensive.
There are quite a few posts on these less expensive magnetic scales the performance has been dismal. Yuri also posted some information if you want to use them with his touch DRO, I believe he ended up with scales from Electronica which were much better.
If you really need accuracy, and reliability maybe consider industrial systems from Newall, my favorite for DIY as the scale mounts work fantastic and are easily aligned. I Also have accurite or Heidenhain systems but pretty expensive. it’s a big step up from some of the imports. Check out Can-do here….
candomachinery.com
I’ve bought 2 systems from them. Very easy to deal with.
Can-Do Machinery Sales - Specializing in Digital Readouts - DRO's
candomachinery.com
I’ve bought 2 systems from them. Very easy to deal with.
I'm in the process of setting up my TouchDRO using a Ditron magnetic scale like that one on my lathe cross slide. I brought home a 6" gauge block from where I work, to use to calibrate my scale. I'm just learning how to set up the machine, but first time out, calibrating, and I got within .001" at 6". And I couldn't see the dial of the test indicator very well. I'm confident that the scale is at least that good, but I'm expecting better, to be honest, once I get it really dialed in.
Five years in and very happy with mine. Glass scales with read-head slots pointed down and provided protective covers over the top. Plenty of oil but no coolant and no problems.
https://www.aliexpress.us/item/2251832534763300.html
https://www.aliexpress.us/item/2251832534763300.html
The issue with the cheaper magnetic scales is the linearity of the scale as well as the incremental deviation at any point in the scale. Unless one maps out the scale at deferent measurement points, one never knows the deviation at a specific point, which is something Yuri pointed out in his review of some of the magnetic scales. Ditron indicates that deviation of their magnetic scales can be up to 0.002" over 1", this is not improved with their 1 micron reading head, so it sounds like it is a problem with the magnetic scale. It may also be the pitch as well as the uniformity. If you were to use the same magnetic scale in diameter mode on a lathe the error would be double. I have the 5 micron Electronica magnetic scales on my mill, I have measure them several times with 123 blocks as well as milling accuracy and typically I see a +/-0.0002" deviation which is at the level of what I can measure. The Electronica and SRA magnetic scales come with calibration certificate, which I have posted, and the 5um scale has a deviation (+/-0.001 or 0.002mM) which is 20 fold less than the Ditron 1um scale (+/-0.02 or 0.04mM). I would say that is a massive difference. Robert in the same post below tried the Ditron 5 and 1uM scales and had similar issues as well as a reliability issue with the Ditron display, the scale deviation issue was resolved when he installed an Electronica magnetic scale. As I previously mentioned, if you are looking at the cheaper magnetic DRO scales, then you would be better off going with glass scales, better/accurate magnetic scales and displays are at a higher price point.
5 Micron SRA accuracy report:
www.hobby-machinist.com
1 Micron Ditron scale specifications
5 Micron SRA accuracy report:
Ditron vs Sino...wich is better in your opinion
I set it up like this: My 123 block measures 3.0005 in length. My DRO is reading this as 2.9986. That is an error of .0019. Way too much to accept. On the 2" side I get very good correlation. I just seems like the scale is off in certain locations.
www.hobby-machinist.com
1 Micron Ditron scale specifications
my original question was are the existing scales out of operation or not if they are still functional can you adapt a touch dro unit to read the currently installed scales?
The y scale is working but not the x
If you swap the scales at the back of the display, does the error follow the scale, or the display input?
What I have read is that the Textron DRO scales did not use standard signaling used in current scales, so if the scale went bad (or the display), you would need to find a NOS/used replacement. If it was just a pinout or connector issue there are sellers that sell glass scales that are adaptable to some of the older DRO's. Given the age of the DRO, you probably would be better off just replacing it.