I present my pen refill adapter, for use in pens that take the Parker Rollerball refill. It allows such pens to use the Parker G2 refills instead (not included).
The Parker RB refill is around 115mm long and 7.0mm in diameter. The Parker G2 refill is around 98mm long and 5.8mm in diameter.
The Parker G2 refills come in many varieties of ink, which are not available in the Parker RB refill size, so this adapter exists to hopefully provide flexibility, between your favourite pens and refills.
The adapter needs to be printed in the polished white or coloured plastics, as the smooth polished finish is functionally desirable.
The adapter comes in two sections: Top and bottom. These sections are connected with sprues which will need to be removed with sharp side cutters or a craft knife. Since the coloured plastic versions are dyed, cutting away the sprues will expose the white underlayer, so coloured plastics are not recommended.
Some powder may need to be removed from the adapters top section, with a pin or thin metal rod, before inserting the refill. This section may also nee to be drilled out, with a 2.5 or 2.6mm drill bit, if the Parker G2 refill's tip won't initially pass through this adapter section.
Due to the very varied nature of pen design, I cannot guarantee that this adapter will work with any specific pen, although I've made every effort to make it as universal as possible.
I plan to make as many refill types compatible with as many host pens as possible, so If you have any suggestions on refill adapters, please let me know and I can hopefully make it available, depending on the relative sizes involved. I have now createdÂ dimensioned drawings of over 80 standard and obscure ballpoint, gel and rollerball refill types, so I like to think that I have a fair idea of what is and isn't possible.