V3 Dual Nozzle Height

Hello all. I’ve got a Taz5. Just got the V3 Dual (finally!) set it up (was a breeze to install and update) and did the gears print. It came out nice enough. The bottom is a bit rough compared to the single extruder, but still quite good overall.

After looking at it closer, I could see maybe why the first print bottom was so rough. It appears the nozzles are slightly offset (in Z) by around .2 or so mm. Easily enough to pass a few sheets of paper when leveling them both. I didn’t realize it but the right nozzle (the PVA one) was practically dragging the PEI when the Left was doing it’s first few layers.

Are they supposed to be offset in Z like that? It’s the right nozzle that’s low.

There are a couple of ways of fixing this with varying levels of ugly:

Level the X rails (plenty of examples how to do this in the forum)
Carefully quantify how far off the nozzles are (feeler gauge, try to get to 0.01mm accuracy)
Turn off the TAZ
Measure how far apart the Z screws are (?400mm)
Raise the Z idler on the side with the low nozzle by low_amount * z_screw_dist / 13mm (the inter nozzle distance)
Example: 0.2mm * 400 / 13 = 6.15mm (yes, quite a bit)
The Z lead pitch is 2mm so you could manually turn the lead screw by roughly 3.1 turns to raise the end
I had to raise mine 4mm to get the V3 level, z still worked okay.

Level the X rails
Remove any filament
Get the toolhead in a position where you can measure both nozzle heights
Turn off the TAZ
Unscrew the heat sink fan (2 longer screws, 2 shorter)
Put the shorter screws back in the longer screw holes to secure the heat sink while pressing the heat sink up against the green printed part
There are two small setscrews that secure each hotend in the heat sink, loosen the setscrews on the higher nozzle
Slide the higher nozzle down until it is even with the lower nozzle and tighten the setscrews
Put the fan back the way you found it with the heat sink pressed up against the green part
Measure and repeat

Level the X rails
Get the toolhead in a position where you can measure both nozzle heights
Turn off the TAZ
Remove the mounting screw from the toolhead and try to reseat the toolhead in a way to correct the offset
Repeat until happy

All of themethods are fiddly. #1 is easier for small corrections, but will produce some large autolevel corrections. #2 took me several tries to get right, but every time you swap toolheads things are off again. #3 is good for people who think hope is a plan.

Thank you!

The #2 method was the one I eventually chose, but the #3 was diddled with for at least an hour. Hope indeed! So cloooose.

I think I may have a better solution to this issue:

Start with removing the front fan.
Then using a 1.5MM allen, loosen the 2 set screws (vertical) That hold the shaft in the heat sink.
Then with a metric ruler, measure the the un-even nozzle to measure the same as the other nozzle (normally they are 2.1mm (hot end top to heat break).
Then tighten the set screws and install your fan and you are ready to print.