Choosing a DRO for a lathe

I have glass scales on my current lathe and also had them on my previous mill, my current mill uses magnetic scales on all 4 axis. I am not sure of the value vs. cost of using magnetic scales on the lathe unless you plan on running coolant. Even then, I rarely hear of an issue with contamination on glass scales with the exception of some of the cheaper Chinese scales with a single seal. Magnetic scales are less finicky as to alignment, can be cut to length, and are a bit more immune to swarf, but I would not install them without a cover. Magnetic scales are still expensive relative, like twice the price in comparison to glass scales. On a lathe, I recommend a slim line 1 micron scale for the cross slide. There are also lathe specific DRO displays, or the graphical units have program settings vs. generic display units. You could consider a 3 axis unit, and put a scale on the tool post slide or tailstock, but it gets expensive and often the scale my not fit or be too bulky. My preference on the tailstock is to have a stand alone battery operated DRO, much less bulky/expensive. The clamping collar I use is adjustable as to its position. I use an Igaging Absolute, it maintains its position and the display is easy to read, otherwise I often see individuals using a caliper or depth DRO. On a mill, if you run 3 or 4 axis, the magnetic scales are a bit easier to mount and more compact, in particular for the spindle. The EL700 will also sum the knee and spindle axis, and has a host of other features that I commonly use on the mill.

Probably 3 levels/costs as far as DRO systems commonly installed
$250-300 range, 2 axis Sino system with glass scales, Igaging Absolute scales on smaller lathes or Android based system.
$400-600 range, 2 axis ES-8A or ES-12B or C or EL400 with glass scales
$800+ EL400 with magnetic scales, Acu-Rite Vue or similar mainstream brand with glass scales, the price almost doubles with magnetic or inductive scales.

On the display units, if you go with a standard numerical LED display, they are all pretty similar. The lathe specific EL400 is very nice. I prefer the graphical displays, I just find the numbers a bit less fatiguing then the numerical display units. I have installed DROs from Easson ES-12 (now ES-12B or C), Acu-Rite VUE an EL700, all are very nice. The EL700 has a great display, but is pricey, in the mid price range color graphical displays I would look at the Easson ES-12B or C (difference is one is vertical and the other is horizontal ) with glass scales they run $650-700.

http://www.dropros.com/DRO_PROS_Easson_Lathe_Digital_Readout_LCD.htm
http://www.dropros.com/Electronica_...#Electronica_Magnetic_Scale_2_Axis_Lathe_Kits:

Tail stock DRO example
Igaging Tailstock DRO 1.jpg

ES-12, AcuRite VUE graphical displays
DRO Displays.jpg

EL700 graphical display
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Magnetic spindle scale
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Bruce. Does TPAC offer different quality display units? Can you comment on how happy you are with the screen colors/clarity/sharpness of your display?

Reason I ask, I've noticed Newell offers two or three choices of displays. Good, better and best sort of thing. But the high end stuff is to expensive for my budget - although probably necessary in a production shop. But I am wondering what is the best heads up display at moderate cost, available for hobby use?

Thanks
Glenn
Hi Glenn,

I think TPAC uses mTech units, maybe Sino or Sinpo. No options offered for different displays. No nice graphics or multi-colors. Bright yellow-green large LED's. Good visibility, lights up like a Christmas tree. Only issue I've had is working in low temps so I have a heating pad on my display during the winter.

Bruce

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I mounted an iGaging DRO on my tailstock. The scale miunt was designed and placed so it didn't reduce the quill travel. I mounted the scale on the back side as it weas out of the way there and was a cleaner look.

One concern on the Grizzly 602 tailstock is the anti-rotation key. Grizzly uses a set screw as a key which effectively gives a single point of contact. Under heavy drilling, the set screw is deformed and the tailstock can jam. With a DRO scale mounted to the quill, the scale will rotate slightly which can cause problems with readings or possibly damage to the scale or pickup.

A dog point set screw won't work because the keyway is as wide as the major diameter of the screw. There have been several solutions to this problem. One was to drill and tap the hole for a larger set screw. The OEM screw was an M8 and tapping for an M10 would permit an M10 dog point set screw to be used. Another solution was to make a special screw with an 8mm cylindrical head and screw driver slot on the other end. I opted for the second choice.

Getting the screw in was a bit tricky since the lead screw has to be removed in order for the the key screw to be inserted from the onside of the bore. The screw was put in place with a pair of hemostats and a screwdriver inserted to through the tapped hole to pull it key screw in. As I recall, the thrust washer had to be modified in order to clear the key screw when reinstalling the lead screw. The result was a positive quill key with minimal rotation.
Tailstock DRO 2 .JPG Tailstock DRO.JPG Tailstock Key Screw.JPG Tailstock Scale Mount.JPG
 
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