UPDATED 4/1/2019 with improved spool holder
I designed this to solve the problem that 3D pens have no system to feed filament, instead letting it hang from the end of the pen.
The spool is perfectly sized so that you can roll on the filament 'sample size' for pens. It works very smoothly in use.
The spool fits the popular DIKALE pen and anything the same size, but also has a desktop stand if it doesnt fit your pen, or if you simply prefer it.
Everything screws or clips together, no glue is required.
Be sure to read the post-printing instructions to put it all together.
For everything except the stand I used 100% infill. They are small pieces that take some stress and need to be solid.
It is essential that you ensure support is turned off - the spool holder arm will not clip into the clasp if support is used (there will be hidden support inside the clasp)
The stand you can print with the usual infill settings.
1. Print and assemble the spool
The two halves of the spool are threaded and screw together perfectly. Hook the end of the filament in the specially angled hole and wind it on.
2. Assemble the spool holder
Make sure the axle of the spool holder faces inward directly over the ring clasp
Push the arm into the ring-clasp. It may feel like it doesnt want to go but it will. Dont be too forceful, but be firm. It is a tight fit, brace the ring clasp on a table and push carefully and firmly all the way until you hear it click. This is a once-only permanent join, you will not be able to remove it, the two pieces have become one.
3. Clip onto the pen
Its another tight fit, but it fits. Push the ring clasp firmly onto the pen - push harder at the back end where the black top feature of the pen meets the white body. Youll hear another click as it clicks into place.
You can remove the clasp from the pen and replace it whenever you like.
4. Put the spool onto the spool holder and screw the cap into place.
The cap stops the spool falling off.
Note that the improved spool holder has a much shorter spindle and it may seem as if there is no space for the cap. There is - just screw it on as tight as it will go, it holds the spool exactly in place.
5. You're done!
Now you can easily use filament with your 3D Pen.
6. If you have a different pen
You can use the desktop stand to hold the spool. It will need a weight (I am using a spool of solder here) or you can hook it onto a nail or hook on the table or wall using one of the holes in the stand. You could also use 'blue tac' putty on the table to hold it in place (the putty that is used to stick up pictures and stuff).
Note how the centre of the stand is slightly off centre to the right when you put the clasp ring onto it. This keeps the centre of gravity for the spool right in the middle so it doesn't fall over.