Keychain loop's position changed to be on top of the heart so that you could use it as a pendant on a necklace or as a car's rear view mirror ornament! Update 10/17/12: I printed this out at 20% fill like everyone else but it broke. So, to increase durability, I printed it out at 50% fill. However, at 50% fill, the plastic heart is hard enough so that it won't deform anymore to accomodate the large diameter pins. Therefore, I redesigned the pins to be smaller in diameter so that it could be easily assembled. Update Nov 1, 2012; New skinnier pins designed and the heart gears's stl file was recompiled from source and reposted, "keypins6, platenokey4b." Update Nov 24, 2012; updated to new pins and key. I found out why some people get perfect fit while others mysteriously have pins that don't fit or was getting perfect fit and then suddenly gets pins that don't fit. Small features such as these pins are much wider than as seen on CAD software because the plastic's first layer is squished against the HBP, causing the first layers to be wider than they are supposed to be. Furthermore, the holes on the gear pieces are smaller than they're supposed to be for the same reason. Also, the holes on the central hub are not printed on the HBP so they are more size accurate. Therefore, there is very little print size variability tolerance so if your machine is slightly calibrated differently, the filament is slightly different in diameter due to different humidity levels, etc, then the affect on the pin size, though small, may cause it not to fit anymore. In other words, the pins are almost too big for the gears while almost too small for the central hub. I improved the pin design by making one end wider for the central hub while the other end is narrower for the gear pieces. I also shaved a little bit of width off the pin heads and the central key. I also included slightly smaller and slightly bigger versions of the pins and key, just in case. Perfectly sized and shaped pins and key file is keypins12.stl. Bigger perfectly shaped pins and key is keypinsbg.stl while its little sister is keypinssm.stl . Problem solved. Enjoy! I invite you to visit 3dPrintFileMarket.com to enjoy the Original Technology Accelerator App for more cool downloads of 3d Printable Stuff. Latest and best version are files PlateNoKey4b.stl and keypins12.stl.Key printed at Makerbot Replicator default settings except 99% fill, no raft and 0.2 mm layer height in ABS. Everything else printed at Makerbot Replicator default settings except 40% fill, no raft and 0.2 mm layer height.Assembly instructions; Check out the following video in slow motion to see where each piece goes in relation to the other pieces. http://youtu.be/SRU2ZG2oULUEnjoy!