2014-08-06: Uploaded a version for 6.35mm shaft as requested.
2013-10-18: Changed the files to two new designs in pretty high resolution. They are 20mm in diameter and 33mm high. It has 15 turns. When you use 2 turn for driving (as I do in my Rostock since a year) 13 turns for movement will remain.
20mm * 3.1415 = 62,8mm
62,8 * 13 = 816mm --> This should be enough for your ultimaker.
I'm going to build my own derivate of an Ultimaker. I want to use the fishing line setup from my Rostock Delta Robot instead of a tooth belt. These are the two pulleys.
- one with a 8mm hole for the axis' and
- one with a 5mm hole for the stepper.
Feel free to ask any question.
print the parts from ABS with a layer height of 0.175mm and you will get great results.
Adding a photo later.