I wanted to show the tap that is used for pens only, from a respectable company, just to support my original question in Phil's thread about the first tap on Bock, which is sought after option. The tapered part is intentional by the manufacturer so the pen turner would know when to stop threading. Once you reach the maximum depth, just put the nib in. You will not need to test it every few millimetres. Of course you could go all the way as it is a through hole, but it is not very pretty on the other side where the cartridge/filler/converter goes. Whoever made a kitless pen should know.
As I understand it (threading) the better option would be the second or third for section on fountain pen materials (plastic, ebonite, non-ferrous metals). Of course the first should work.
