Servicing a Stephens' stud-filler

[Paul-in-SF]

I hadn't seen a filler quite like this before. By the way, I don't know the model name or number; it is a very simple and plain black pen with gold furniture and the top of the cap and bottom of the barrel are flat. It is 131 mm long capped, and the barrel just says Stephens' in script, and with the apostrophe. 

 

The back end of the barrel unscrews just far enough so that you can press the whole thing in, like a button filler, and (I presume) it fills a sac inside using a pressure bar. Which is fine, but it doesn't seem to be working very well. It doesn't take in as much ink or water as I would expect, so I would like to see if there is any problem with it, and try to make it function better if possible.

 

How to remove the back end, though? There is a small hole in the side of the brass stud, under the rear cap, which I suppose might be used to unscrew the back assembly, but I would like some advice before I try it. I like the pen a lot, and I don't want to break it. Also, the section seems quite easy to unscrew except that it seems to be getting twisted up inside so I stopped trying that. I thought it would probably be better to remove the back first, and probably take out the pressure bar before removing the sac with the section. 

 

If anyone reading this has any experience with these pens, I would be grateful for some advice, and anything to watch out for as I try to proceed. 

[eckiethump]

A lot of the time the "button" mechanism freezes up with the aluminium construction oxidising, which also makes unscrewing the back end difficult at times to unscrew. The pressure bar has to be exactly the correct length to operate, if bent at all pen will not operate. After back end, section removal and re-sac, re-assemble taking great care not to twist the pressure in the barrel.

Eric

[Paul-in-SF]

Thanks. Was I correct that the little hole in the brass stud intended as an aid for disassembly? What kind of tool should I be using?

[Paul-in-SF]

I went ahead and tried to remove the back end, and it came out easily with a little gentle help from my section pliers (and no, that little hole doesn't seem to play any particular role that I can see). Then the section also came off easily, and the sac was intact and in good shape. The pressure bar appears to be the problem, it is rather corroded and the metal is rather thin, so it is not strong enough to compress the bag completely. I happened to have a new bar of the right size, so I put it in, and now the pen is filling much more effectively. I'm ready to give it another fill 

 

By the way, as I was looking around online for inspiration, I found this very short video about how a button-filler works. I knew the basics already, but this presenter has a cutaway pen that shows the pressure bar actually compressing the sac. Seeing it like this really hits the point home for me (for one thing, I've never quite understood how such a short-throw button push could really compress the sac so completely). The video is in German, but I don't think it matters, it's the demonstration that counts.