Dial indicator

I know the taz can print great right out of the box…however I see several of us are noticing the ‘z’ axis can be off and are trying set it…I’m one of them!
coming from a cnc background where measurements are critical and things must be flat and level we use digital calipers and ‘dial indicators’ a lot…so what’s a dial indicator?
well for those of you that might not know it is a instrument that when at attached to the traveling head can check the surfaces for ‘flatness’ …first you lower it to the surface then turn the dial to ‘0’ then jog the head over to the other side while you watch the needle go up or down checking for flatness and how much it’s off…okay got it?
well my right side is off so here’s where I’m at so far
stripped the bed down including the wiper (notice the wires to the base plate are all tight against the frame and hole…hope they never short out!)
went to menards and picked up a 4’ piece of alum U-channel cut it down to make some supports for the glass bed then ran my dial indicator from front left to front right…
my left is ‘dialed’ to ‘0’ in the picture, jogged to the right notice the gap jogged it to the back right it’s off so I’m thinking the ‘z’ rod needs a turn or two to bring it down…not sure I I have to turn off something or turn of the machine and turn by hand …I don’t want both spindles turning on me any help let me know or it’s time for a call

To prevent both Z rods from turning while adjusting one unplug one of the wiring harness’s going to the motor.

To adjust the leadscrew manually, with the machine off and unplugged from power and usb, unplug the motor harness from the motor, then manually turn the motor. The easiest way to get consistency on both sides is to measure with calipers from the bottom of the leadscrew nut down to the top if the lower leadscrew bearing. That number should be identical on both sides.

Using a heavy clamp like that to mount the indicator has the potential to flex the rods down in the center which msy lead you to believe you have a slight hump in the middle of the bed. That’s less present in the taz 6 with the 12mm x rods, but they are still unsupported.

the clamp is not that heavy or heavy enough to make the rods bend

went to the machine shop today to make a few more measurements i have a short 1 minute video of our findings on my phone you will find very interesting but when i try to post says it’s too large to post… how can i post it?thanks…