This is a spool holder designed to sit on top of your bukobot frame. The spool bracket was designed with a 6mm hole for a steel rod or such rod. Anything larger and you might be able to scale up about 10% . otherwise the hole has to be widen by hand. I will upload an STL file without the hole, you might be able use scad or such program to put a hole in. The spool it was designed for is a 50mm hole and a depth of about 14mm. I made it specifically for prototypesupply.com 2kg spools. The retaining bracket for the spool will not fit tightly so you are able to remove it if nessesarry. It should require a little force to insert it but once its in it won't fall out easily. Any comments or suggestions are welcome I printed these with PLA but i would imagine they will print fine with ABS. Print out 2 of each: bracket and bracket holder. Should spin with no issues.