Review on Iverntech MGN12 400Mm Linear Rail Guide Upgrade For Ender 3, Corexy, Tronxy, Delta Kossel 3D Printers And CNC Machines With Stainless Steel Carriage Block by Paul Walters

If you don't care about consistency in the preload, these are going to be good. Unfortunately, I was using these to improve bed slop on my ReDuplicator MK3x, which introduced enough slop on one of the rails that I didn't notice in time to return.I tried to replace the bearings with G25 to ensure consistent ball diameter, and it became more apparent how inconsistently the blocks are machined. One block has really great travel, another is good, and the other is terribly grindy. If I were to look more closely, I could probably diagnose the nature of the grind, but I don't have the tools to rework the entire block, symptom by symptom.I think the takeaway here is that 3D printers need more preload consistency to ensure there is no drag in the movement. If you have the tools to re-machine the blocks, these are probably good enough. If not, you should probably invest more into HIWIN or another reputable brand.