Summary

This is version 2 of my 50mm spool adaptor for hard drive filament spools. This one is thinner and not wonky! It will take less time to print as less material is used but remain perfectly strong.
The outside rim is 10mm high and it's enough to use this adaptor directly inside the hardrive without removing the bearing mounted on a plate.
v1 version
http://www.thingiverse.com/thing:378071

Instructions

A few tips to print this on a kossel cold bed
First layer speed need to be brought down to below 20mm (putting the first layer down faster will increase the chance of the piece warping of the bed)
When printing big part on a cold bed you need to slow down the print speed no more than 40mm
By reducing the speed we are trying to avoid the plastic being stretch while is deposited. The plastic will already be affected by the hot/cold contraction issue, no need to add stretching that will make the plastic contract even more.
First and bottom layer need a lot of plastic to be deposited this mean that even at slow speed lot of plastic is going through the extruder meaning the temp go down quite quickly. First layer temp at least 220. If I set the temp to 210 it usually drop to 195 while printing first layer and bottom layer (perso I do set the temp at 230)
I use a brim of 12mm one layer of height. This will highly help avoiding the warping (if you go slow enough) I perso use such a big brim to a evaluate the first layer deposit if each loop do not bond with the next you can stop your print and somnething is most likely calibrated wrong or your layer are too thin.
Start the extra cooling fan after the 2nd layer is deposited be patient for this second layer to be finished that start the fan. NOTE: no fan = warping for me (and a lot of it)
Please don't hesitate to drop me a message or comment if you have question.

v2 50mm inside spool adaptor for hardrive 25.5mm bearing