Igus 8mm bushing and SC8UU compatible housing

thingiverse

The bushings are crafted from high-quality Igus filament, measuring 8x12x12 in size, while the housing is designed to accommodate various materials such as PLA or ABS. Igus provides STL files for their standard press-fit bushings, but these tend to be too thin. In contrast, the custom-designed bushings are thicker and slightly oversized, allowing users to easily shape them into precise sizes and finishes before installing them via a press fit method. To achieve a smooth exterior finish, users should employ abrasive materials or files; however, for the interior surface, it's recommended to utilize a reamer or a sharp drill bit once installed to attain the correct diameter and finish. When done correctly, this approach leads to virtually zero play and ensures a seamless travel experience. For linear motion applications, bushings with grooves work best, as they are smaller, shorter, and lighter compared to the Chinese LM8UU series. Additionally, these bushings can be paired with affordable SS rods, which is not possible with ball bearings due to their softness. The housing is compatible with the SC8UU, albeit slightly shorter, requiring only two screws for installation. Self-tapping screws of 3.2mm in diameter are suitable options; larger screws may necessitate drilling holes before tapping. One notable advantage of these bushings is that they do not require messy lubrication. To ensure proper alignment, users should utilize the smooth rod to facilitate the process. In contrast, most 3D printers employ a poor engineering practice by splitting the housing and using tie-wraps due to design and alignment issues. Fortunately, the elasticity of the assembly can cope with this setup. Visual examples of these bushings in action can be seen on the pictures, featuring installations on the Geetech Prusa Al Y table (using a previous non-press-fit design) and integrated into my own X carriage. For optimal results, heating the housings with a heat gun after installation can help relieve stress, as demonstrated with the Y table setup. Notably, these bushings have been in operation for several months, handling loads of up to 1kg spool without issue. The resulting assemblies are significantly lighter, with the Y table weighing over 150g less than its original counterpart and my X carriage plus extruder, hot end, etc., coming in at around 250g – less than the weight of a single MK8 Nema 17 motor. An added benefit of these bearings is their ability to dampen vibration and operate quietly, unlike LM bearings that produce a rattling noise. While this may be perceived as annoying by some users, it's worth noting that misaligned LM bearings will eventually fail due to stress caused by improper installation. In conclusion, Igus supplies drop-in bearings (Drylin) similar to the LM series used in 3D printers, but these tend to result in larger, heavier parts with increased friction. For those seeking a more engaging experience, crafting their own bushings offers a rewarding challenge. Alternatively, users can opt for standard bronze bushings (8x12x12) as a substitute for printed Igus bearings, offering a viable solution for those who prefer a more traditional approach.