We keep a small quantity of Bock size 8 (type 380) fountain pen nibs in stock. Available in steel, gold plated steel, solid titanium, solid 18k gold or rhodium plated solid 14k gold, they are a thing of beauty and are supplied with an ebonite feed and housing for even and consistent ink flow.
Makers of custom pens or so called kitless pens need to know that the thread size is M10 x 0.5.