I want to tell the story here so everyone that reads will be aware. So the thermocouples arrived and I replaced the broken one. The temperature couldn't stay at the place I wanted to again. So I went to the PID controller and tweak the settings to the factory settings and no problems at all. I produced like 2 kilogramms/5 pounds of 1.70 ABS. Te machine is running at 177.5 but I still can't get 1.75 filament. That is not a big problem I assure its the height of my setup that is pulling it. Posting photo.

Yes, the nozzles are intentionally undersized a bit. The reason for this is that some polymers exhibit more die swell than others. In addition filament diameter is a product of how much cooling is provided, room temperature, extrusion temperature, etc.

As a result it is better to provide a bit undersize, as it is easier to make a small hole larger than a large hole smaller. You can just set the slicer of your printer to 1.70mm. Or:

- Drill the nozzle out slightly
- Reduce extrusion temperature
- Increase cooling at the nozzle

Could you please post me a photo to see how to mount the thermistor properly? I use kapton tape. thank's.

wondering about that too but reckon the final position rest on how much tension used in tightening.

  what i done wrap one layer round the nozzle, pieced the hole inserted the  tip all the way in.  then wrap strips round till its held firm!.

Changing temperature or power cycling should not necessitate a PID autotune.

Do I need to calibrate each time I start the machine and when I change the temperature?