Geha Piston Removal - Need Help

[Dr.X]

Hello everyone.

 

Trying to open the rear (piston) end of a Geha (model 790, I think).

 

Saw Bo-bo's suggestion if using a paper clip in the hole below the piston threads, and am unable to figure out how to use the paper clip to open it.

 

The paper clip only goes in a couple of mm. I've bent the ends of a couple of paper clips and can't figure it out.

 

Thank you in advance.

 

Nick[

 

attachment=484016:Geha piston detail.jpg]

[Carrau]

I don’t think I can help you there, but in case you get it apart, you may need this link to put it back together again.

https://www.fountainpennetwork.com/forum/topic/338311-cant-reassemble-a-geha-student-pen/

[joss]

Geha likely had a special clamping tool with a tiny pin that locks into that hole, allowing unscrewing the piston mechanism.

 

You can introduce a paperclip just 1 mm or so, simply because the clip gets stuck against the piston stem (that is the part that is stil attached to the blind cap, see picture in the link that Herrjaeger shared or this picture here, second pen on page).

 

Is there only a single hole or two opposing holes in the threaded bush?

 

EDIT: I just checked one of my Geha pens and I see a single hole so it will be very difficult to unscrew the piston mechnism with just a paperclip

Edited February 3, 2020 by joss

[Dr.X]

EDIT: I just checked one of my Geha pens and I see a single hole so it will be very difficult to unscrew the piston mechnism with just a paperclip

 

 

Yes, one hole. I was hoping Bo-bo Olsen would weigh in. There is one post where the procedure was photographed, but the pictures are no longer available (as they are in many FPN posts these days).'

 

Thank you for trying though.

 

I used to think of myself as handy, but am suffering from a complete failure of imagination with this...

Edited February 4, 2020 by Dr.X

[praxim]

You need a circlet with prong, to put it in mundane terms. Imagine (with a paper clip) the end stuck in the one hole, and then bent at exit to go part or most of the way around the pen in the direction you wish to turn it. Now, turn this, possibly with the aid of a clamping or gripping tool.

 

There are specific tools with handles for this sort of thing but unlikely to be in the exact size you need unless you care to make one.

 

edit:typo

Edited February 4, 2020 by praxim

[Ermennda]

I am thinking of the small wrenches used to adjust micrometers you could find a second hand one and file the "prong" so that it fits that hole.

 

If you search for "how to zero a micrometer" you can see them.

[praxim]

I am thinking of the small wrenches used to adjust micrometers you could find a second hand one and file the "prong" so that it fits that hole.

 

If you search for "how to zero a micrometer" you can see them.

 

Exactly the item of which I was thinking. One can be cobbled up as a one-off.

[Dr.X]

This?

 

 

Interesting. I will have to try making one. Or looking for one.

 

I'm worried because the plastic of the Geha is soft, and in my experience a good deal of torque is required to do this even with soaking and heat.

I'll report back.

 

Many thanks everyone!!

[Bibliophage]

They also have similar tools for plumbing, but MUCH larger.

[Dr.X]

Turns out pen has no leak, so no need for me to take it apart. Thanks anyway everyone!