Kensington Expert Mouse Trackball - Scroll Ring Mechanism (v2)

thingiverse

This was originally [thing 4140712](https://thingiverse.com/thing:4140712), but I've updated it to work for both the wired and wireless versions of the Kensington trackball mouse and moved it under my original account (which I had forgotten I had, it had been so long). Most of the parts have been revised. What This Is and Why It Exists This is a replacement scroll ring mechanism for both the wired (K64325) and wireless (K72359WW) versions of the Kensington Expert Trackball Mouse. I created this because the scroll ring on this trackball is problematic. As Wirecutter put it, "[T]he scroll ring felt gritty when we turned it.... Many owners report the same problem ... 'the scroll ring feels so jerky and janky.'” In addition to turning poorly, the Kensington scroll ring also has problems giving feedback to let the user know that scrolling is about to occur. The scroll wheel on most mice creates a tiny but noticeable amount of resistance immediately before scrolling happens, as if the scroll wheel mechanism has a series of notches built into it. The Expert Wireless Trackball Mouse tries to do this through use of a magnet. However, the magnet works so poorly that many sites recommend removing it entirely. My replacement scroll ring spins on 4mm-diameter chrome steel ball bearings and--optionally, for those of you who are interested--creates scrolling feedback by having a 623ZZ miniature bearing press against a portion of the side of the ring that is shaped like a wave. Caveats - I don't have much time to support this, so if you run into issues don't be surprised to be left on your own. - The tolerances for this thing are extremely small. Expect to do some sandpapering and even that may not be enough for some of you. - In addition to the sandpapering, I also had to use an Exacto knife to clear out the little hairs that stretched across the windows of the windowed ring component (Component6). The longer you spend on post-processing, the better the result you're likely to get. - Assembling this requires that you first disassemble the existing scroll ring, which unfortunately cannot be easily re-assembled if you decide the replacement design is not for you. - I had to sand down the bottoms of the Kensington's top mouse buttons in addition to some nubs between the mouse buttons on the top plate. None of this is visible when the device is reassembled. - I also sanded off the tiny (1.5mm) ball bearing holders on the underside of the cup's lip. You can omit this initially (while seeing if this design is for you) if you don't snap Component8 into place. What's Changed Since I Created the First Instruction Video - The current version has 48 "windows," which is shown in one of the other videos. The Kensington ring has 39 windows. - PrusaSlicer recently implemented a change for "Elephant Foot Compensation" that changes how the first layer is printed so that it isn't wider than subsequent layers. - I recommend setting the value for this at .1mm, because I found this change to be problematic. Assembly See videos for instructions. Videos: https://youtu.be/gQpbLYEUtiM https://youtu.be/QqUpg-sxk5I https://youtu.be/i8YDzRhLhCo