I picked up this indicator stand from Overkill19 the other day thinking it was a mechanical articulating linkage like a Noga. It turns out that it's locked by hydraulic pressure. As you turn the nut onto the thread of the lower pivot bolt (yellow arrows) the lower piston (red arrows) is forced into the bore of the lower pivot bolt. Hydraulic oil is forced through drilled passages up to the upper piston which extends outward from it's bore (green arrows) to push on a radiused piece in the upper link. It was leaking fluid so I replaced all the o-rings ($1.78 from Fluid Seal) added clean hydraulic oil and bled out a small amount of air. Very cool piece and it now works as good a my Noga. I had no idea that here were hydraulic indicator stands but apparently some imports like the ones sold by Grizzly Tools are like this also.
