About this 3D model

After fitting some “self-centering” rollers to my AMS, I discovered that if an odd-size spool has to sit to the left of the guide rail or is otherwise narrow, the spool is tilted over to one side and it wants to move across the rear roller. Unfortunately, I managed to break two of the original rollers getting the bearings off, so when I went to put them back in, I couldn't. Not wanting to spend the money to buy new rollers, I decided to make these simple replacements out of TPU. They print very easily in two halves, they don't use any shafts, the bearings slip on easily and have the dual purpose of holding the two pieces together (no glue necessary!). And I'm confident they won't wear out quickly. I made them slightly smaller than the originals to give a bit more room to the top cover and the TPU surface means the spool gets a better grip on the roller, so win-win! I suggest trying the 3mf profile and I strongly suggest printing these in TPU if you can, though they will print and work well in any material. To “assemble” them, print both halves then while they are being held together, push the bearings onto the ends. That's it! Use glue if you want to between the halves but it's not necessary. The one in my cover picture has been in my AMS for over a week now, and it works flawlessly, dare say better than the original plastic ones. If you can't get the bearings off your original shaft without breaking them you're not alone. They can be stuck on pretty hard and they unfortunately aren't great quality bearings anyway. I purchased 8 x 693RS bearings from the hobby store. They are the same dimensions as the originals but have a rubber seal instead of a metal cover over the race. The dimensions are 8mm outer diameter, 4mm thickness, 3mm internal diameter (hole) . I've seen them advertised as 8x4x3, 8x3x4, 3x8x4… you get the drift. It depends on the seller. Just make sure you check the dimensions. These are to suit the original AMS lower piece. If you have the Hydra mod, you'll need narrower ones I believe. You should be able to resize them in the slicer easily enough.