2/3 Axis Digital Readout (DRO) with TTL Precision Linear Glass Scale Encoder for Milling Machine & Lathe | High Accuracy Measurement Tool | Display & Scales Sold Separately | 700mm (28") Travel Length Scale | Perfect for Metalworking, CNC Machining & DIY Projects

I have a midsize knee mill for hobby gunsmithing. I finally decided to get a DRO and opted for a glass scale. I didn't like most of the methods tor cutting the glass scales to fit your machine and the package DRO kits didn't include the length's I needed. I decided to buy the scales and readout separately but from the same vendor. I may have paid a bit more but I didn't have to cut the glass scales( for me it would have meant entirely disassembling the scale, removing the reader head, cutting the class with a diamond cutter, cut and thread the aluminum housing and then reassemble and test). The scales came exactly the length specified in the instructions. You must give the correct table travel length asked for in the instructions and this seller will add the extra inches to your measurement. Once ordered the package was shipped from a location in the US and arrived at my house in a few days. I knew I had to make my own brackets although one bracket per scale was included as well as metric screws. Making the brackets is no big deal nor is drilling and tapping the mounting holes on the mill. I did have to buy a right angle 20v drill to make some of the holes due to space requirements. Since you have a mill designing and making custom brackets or extensively modifying the existing brackets can easily be done. Design the brackets so they can be adjustable because after scale installation they have to be parallel to the direction of movement. For my work I wanted a maximum of .0015 inches over the entire travel length for x, y and z axis . It required about 1 hour per axis to calibrate indicating the top and side of the scale. Most difficult was the z because of a tapered column requiring tapered shims. Once installed the DRO worked great...no more counting the number of turns or figuring backlash just to name a few. Tested accuracy against the dials I had been using and one turn is 0.125 inches and is exactly that on the DRO provided you line your dial lines correctly as the reader is accurate to + or - 5 microns. If you are using inches the readout will take the measurement in metric units(micron = 1/1000 mm) and convert the readout to inches so although the readout in inches goes to 0.00000 the last number is fictitious.The manual is worthless. It's as if the manual is for a different unit. It references buttons that are not on the unit. So far the unit seems to work. Just setting up now.I disliked the fact that when I recieved the item the box had a big hole stabbed in it and boxed was crunched on all corners, thankfully it still worked but should be shipped in better way!!!works great, easy install, pay attention to all installation instructions including to select the correct setup and machine from the setup menutook some installation work... but works well