The one drawback with this is that it doesn't have a 'lathe' mode. 2 axis DRO packages will have this option that doubles the Y-axis reading, giving a true diameter of a part being turrned. It will, of course be correct for milling.
Step 1: Materials / Tools
~ 6" 3/8" steel rod
~ 6" #8 threaded rod
~ 6" 1/4 threaded rod
3 #8 nuts
4 1/4" nuts
1 Cheap 8" digital caliper
Dremel (Cut off wheels, 1/8" carbide cutter, 1/4" cylinder grinding stone)
3/16" drill bit
5/32" drill bit
Small screw driver (for the digital caliper)
Step 2: Preparing the Caliper
Cut off the inside and outside jaws on the beam (Dremel + cutoff wheel). On the display part, remove the inside jaw and only part of the' outside jaw. Make sure you leave enough of it so a #8 nut will clear the plastic housing. Drill a 5/32" hole.
Make a 1/4" hole in the end of the beam. I found a solid carbide straight 1/8" ball end cutter that worked fantastically compared to the grinding stones I used the last time I did this. Tip: use disposable gloves to prevent the tiny metal slivers from burying themselves in you hand. It's like fiberglass that doesn't wash off :( You could also try attaching a magnet to the workpiece to retain the slivers.
Step 3: Prepare the Cross Slide
Step 4: Mounting Brackets
Step 5: Attach to the Machine
I should note that the end of the beam is just under the hight of the table. With the original 3 jaw chuck I have, the jaws can stick out about 1/4" before they hit the table. Make sure you don't run it into the jaws if you are working on something with a large diameter. As an improvement, I think I will make another 1/4" hole on the table at the bottom edge to lower the DRO a bit closer to the saddle. I can probably drop it about 3/4" which will give me some more clearance.