My ultimaker3 had a default factory extruder step setup of 369 steps/mm. When I tested with 100mm cold extrustion, I got 105.9mm..   y * 105.9 = 36900 y = 36900 / 105.9 = 348.4 (round to 1 decimal) =========================================== SSH root access to your Ultimaker, login after that with: ultimaker/ultimaker.   => 100mm extrusie: sendgcode T0 sendgcode M302 S0 sendgcode G92 E0 sendgcode G0 E100   => Test your new step value first with: