When asking for 100mm of extrusion through pronterface I still see variations of more than 25%. I can't get my estep calibration done. And yesterday a long print was ruined on the last few layers because (apparently) the extrusion rate dropped very, very low to finish the print.

I cannot see slippage of the large gear on the hobbed bolt. I cannot see slippage of the small gear on the shaft and I have tightened the small set screw as much as I dare.

I don't see gouging of the filament by the hobbed bolt, and I am seeing the variability across several different spools of 3mm filament, both PLA and ABS.

The pot on the stepper controller is adjusted (I did not record the final voltage readings when I checked and did very minor adjustments, but they were all very close to the middle of the recommended range). There is nothing obvious to me that says the stepper is missing steps.

The only clue, besides the wildly varying extrusion lengths, I have to go on is a lot of squeaking when I extrude PLA. I tried a little vegetable oil and this reduced the squeaking but did not fix the extrusion problem.

Unfortunately, all of things on my list to check next involve disassembling the extruder. These are the suspects I have identified:

1) The filament path is constricted passing through the extruder body? This explains the squeaking. I did not drill out this path before assembly.

2) The nut on the back side of the hobbed bolt is not tight enough allowing the large gear to slip?

3) The small gear is slipping on the shaft?

Is there anything else I can try before disassembling the extruder?

Thanks in advance.

Jim