This is a classic support for a filament coil using a 3.5 hard disk frame. I designed this to have an adapter to fit small hole 15mm coils and big hole coils. So you simply slide out the adapter to fit smaller coils. Drill the holes as needed or edit the included freecad sources. Assemble the parts and you are done. At print time remember to add support to the base, as it needs it for the central hole. I recommend my other design http://www.thingiverse.com/thing:993827 that performs much better and has lot more options.