D1 to Sheaffer K ballpoint refill converter

This is a converter that will take any D1 refill and converted it to a Sheaffer K ballpoint refill. 

I have print it with 0.2mm nozzle and 0.14mm layer height. I find the less accurate you print it, the tighter the hole is. Hence, I have intentionally make the inner hole larger than it suppose to be accommodate less accurate printer profiles.  Mine fitted perfectly with enough friction the hold the refill without getting it stuck. However, if yours have fitting issue, you can use the scale tool on your preferred slicer to do some shrinkage compensation.