Hi SandverG. And thanks for your input. I've done a few fixtures from 250mm long straight edges to internal bores and cylinders from 11 mm to 40mm. So i did a few benchys to look at the usual print settings temps and cooling performance and these seem to work best with basic plain PLA now. Then I started to print 20mm cubes to adjust again the usual speed and extrusion and print order priority settings. I'm making jigs for QA purposes so have to hand a good range of measuring equipment and having done 3d prints for a few years I'll always ignore things like elephant foot,seams,layer height zits and corner over shoot as thats going to be giving false information. Rather Ill dial the printer in for its media and printing enviroment first and then start looking at actual sizes internal and external. What im getting is a 0.4mm difference between x and y on a 20mm cube but also 0.4mm difference on an internal bore of say 40mm. So its not a step count or id expect that to increase the error in proportion to the print size. This seems pretty well dialed in from the factory tbh but Im not away how the end user could calibrate the steps on the s5 anyhow. Layer lines and size across the different heights all seem within 0.1mm at 3 different points , so Im a bit stuck on how to adjust tbh! Ive changed things like line width to 0.35 for a 0.4 print core. Oh and by different nozzles to hand I mean several print cores. 4x 0.4 aa and 2x 0.8 aa as well as a 0.4bb all new and Im only using genuine ultimaker fillaments such as pla, tough pla, petg, tpu and the pva types. Hope this helps 🙂 no photos at the moment but can take some sample shots of 20mm cubes and fixtures etc tomorrow. I hope the OP doesnt mind Ive jumped on this thread but its the closest Ive come to finding the same symptoms being discussed. Print core nozzles are clean and fillament leaves the nozzle vertically. I did manually check the bed for level this morning just so its not only relying on auto leveling to sort out any run out ( which it does rather well tbh!)