K8200 extruders custom fishbone gears . New gear ratio is 9/47 Notice If you change these gears you need to calibrate your extruder stepper motor becouse gear ratio changes little. Use this tutorial http://www.instructables.com/id/How-to-calibrate-the-Extruder-on-your-3d-Printer/?ALLSTEPS yes it's made for solid doodle but basics are the same. Upate 7: Size problems is fixed now. Thanks to balthazar for testing the gears. I uploaded all new files these are untested with printer, but they are tested in 3d program. Update 6: Uploaded design without "k8200" text for those who like it more without text. Update 5: New V3 version uploaded. minor fixes. now 20% smaller so it fits better to k8200 extruder. Update 4: Finally fixed problems. Fully working teeths. Update 3: Majore flaws in teeth dimension. Fix coming soon. It wasnt good idea to upload before testing. Sorry for inconvience. Update 2: Uploaded fully working model of version 2.1 Update: I found way too many holes in big_gear so i deleted it and i will upload when i get it fixed. Be sure to download correct version of the gears. There is couple different models. No text only hexagons K8200 text and hexagons