8mm Self aligning Igus bearing type 2

thingiverse

Based on my previous thing: http://www.thingiverse.com/thing:1824584, only the mounting system is different. Dimensions are 32 by 20, with a height of 12mm. In the provided picture, it's clear that the object was made from ABS plastic and the holes were drilled to accommodate M3 screws passing through them. If you're interested in a similar design but with a different mounting option, check out this alternative: https://www.thingiverse.com/thing:2108914 To prepare the bore for the rod, start by smoothing the inside surface using a spherical sanding tip about 12mm in diameter or something similar. Next, use sandpaper or a smooth file to smooth out the Igus sphere on the outside. Finish the bore with an 8mm reamer and then check it with the smooth rod to ensure minimal play. If you don't have access to a reamer, you can use a high-quality 7.9 mm or 8mm drill bit as a file (quality bits are ground). You don't necessarily need to use hardened steel rods; regular smooth stainless steel rods found in cheap kits will do the job. Aluminum rods are also acceptable, depending on their finish and intended use. Igus offers excellent options with the right anodized finish. The STL file provided has 2.5mm holes spaced 24mm apart, which is slightly smaller than usual for a printer output. As a result, you can use self-tapping screws (diameter 3-3.2 mm) or regular M3 screws without needing to tap the holes first. To avoid cracking the plastic, you may want to drill to 2.5mm instead. Whenever possible, it's recommended to use self-tapping screws, which are easy to find or salvage from old office equipment. In the United States, measurements are often expressed in unusual units (old wire gauge), but simply measuring the diameter will suffice. A diameter of 2.8-3.2 mm is perfectly fine. I'm surprised by how many people try to insert regular hex nuts into their designs, making the part more complicated and fragile when self-tapping screws would be a better choice. This drives me crazy! If you need to frequently mount or dismount parts, consider using threaded inserts, which are standard in the industry (and can often be sourced from old office equipment).