Hi folks,

I was chatting with somebody the other day. My chattee is very familiar with Vac-Fills, and declined to answer directly when I asked how they were made. The game is afoot!

Here's the puzzle. At the front end of a vac-fill the thread that holds the feed (Triumph) or section (open nib) in place has a smaller inside diameter than the section of the barrel just behind it (the bit that releases the vacuum). So the barrel has an ID of (say) 7 mm for 8 centimetres, then close to the nib the ID is 8mm for about a centimetre then narrows again to around 7mm for about a centimetre. This last part has internal threading for the section/feed and also sometimes external threading. (Reading this back it seems complicated!)

I don't know how the larger internal diameter is made, and that's what I'm curious about. You could do it with an expanding tool, but that's a lot of work and person hours per pen. Anybody have any ideas?

Of course, if I have misunderstood I'd be happy to be put right!

Cheers,

Ralf