I have several coils of multi-coloured loose filament which I wanted to use on my Replicator. This spool design allows for easy resizing of the spokes for fitting into loose spools of filament and reuse on other spools. There is no need to wind on the filament as with some other solutions. I can mount both the smaller but thicker USA sourced filament coils and the larger New Zealand sourced filament coils on my Replicator. Options are provided for mounting on the back of a Replicator 1 (and possibly other models) as well as for external spool holders running on an axis away from the Replicator.
Update 19 May 2013: Thanks to a heads up from MobyDisk I have made a small change which fixes a problem when printing the hub using Repg.
The spool I have designed has hexagonal spoke sections which can be stacked for various widths of spool. It is easy to extract a spool from one lot of filament and use in another different width filament loop by using stackable spokes.
Each complete spoke has a bracket at the end to hold the filament loop. The other end of the spoke inserts into a central hub which spins around the axis of support.
1) Choose and print either the Replicator hub or the external hub as required and print with support. The Replicator hub should fit on the spool holder fairly snuggly with some wriggle room to allow for unwinding.
2) Print a bracket with support and check it is a suitable fit for your spool. The wide 50mm bracket is needed to allow unwinding on the back of a Replicator with minimal jamming (see photo). You can use narrower brackets for external spools. Once you are happy with the fit of the bracket print 2 more.
3) Estimate the length of spoke required by positioning the Hub and Brackets. USA sourced filament typically needs 20mm spokes. The spokes are stackable with a minimal size of 5mm so you can print out smaller spokes to stack on larger ones. Small sizes of spoke (5mm) need to be printed with a finer profile. Spokes MUST be printed vertically otherwise they will split.
Note that the fit of the spokes into the hub and brackets depends on the resolution of your print. It is not necessary to completely insert the spoke into the hub or another spoke providing there is some grip to hold the spoke inside the spoke hole.
The fit of the loose filament on the spool should itself be loose. It should be fairly easy to insert the final spoke and bracket inside the filament. If the filament is tight you can have problems with the unwinding.
If you are using larger coils of filament like those from New Zealand you can only mount these on the left hand side (from the front) of the Replicator as there is no room on the right due to the power and USB cables.