Osmia Piston Repair

April 26, 2017

Checking out this thread:

https://www.fountainpennetwork.com/forum/index.php/topic/231019-replacing-the-piston-seal-in-osmia-446/

I get some idea of how the rear unit can be removed using the paperclip to apply pressure without crushing the threads.

My pen is an OSMIA SUPRA 36, so I presume the method is the same would work.

Questions:

1. Does the rear unit have a right handed (normal) thread, or a reverse thread like some other German pens?

2. I saw a recommendation to use a split brass nut instead of the paperclip in this thread:

https://www.fountainpennetwork.com/forum/topic/271672-osmia-piston-repair/?hl=osmia

Would a wrench designed to remove a Vacumatic filler unit also work - mine is brass with a nut to tighten it. Not sure threads would exactly match.

Thnx,,

.

April 27, 2017

I have repaired many Osmias/faber-Castells successfully and their piston units are easy to remove. First, take paperclip and make this kind of tool. Important is that is has that little hook at end, which goes to the little hole.

And then you need to heat barrel, these crack really easily. I use hairdryer. When applying heat, I keep my fingers close where I am heating, so that I don't over heat. When it's too hot for my fingers, I turn off the hairdryer. Then I use this little tool. It should wrap around pen like this:

And then you can really carefully turn this tool, no need for pliers. If it don't work right away, heat again (you can leave this tool on place when heating) and then try again. Sometimes it takes many tries before it start to open. All my Osmia/faber-Castells have threads this way. But if it really feels like it wont open, try other way too. But really carefully.

And when you take piston out, mark where the piston turning knob is. You will need it, if you don't want to have gab between knob and barrel. And when you are screwing it back together, just put tool in whole opposite way. I really like this tool, because it only turns one way, easy to remember right direction.

This is how I do it and it have worked every time. Takes bit of patience and some finger strenght. If I really need to use pliers, I use it to hold the tool, without touching the pen. It also help, if you hold pen with gripping material.

I wouldn't use any metal thread tools against old pen threads, it easily damage them , if it is wrong size. Which I suspect is, because German use different standarts and metric units, and Usa uses imperial units. If you are talking about parker Vacumatic wrench. Also it's more than diameter that have to mach, also thread pitch.

Hope this helps a little. I would love to see picture of your Osmia Supra

Edited April 27, 2017 by Inksomnia

April 27, 2017

And when you take piston out, mark where the piston turning knob is. You will need it, if you don't want to have gab between knob and barrel.

THANKS! Very helpful.

But could you please explain exactly what to mark?? The turning knob, or the screw-in unit?? Before I remove anything, or after??

thx,

April 27, 2017

THANKS! Very helpful.

But could you please explain exactly what to mark?? The turning knob, or the screw-in unit?? Before I remove anything, or after??

thx,

Ah, when you are removing the piston from screw unit. Mark where the piston turning knob is on threads, when piston falls out. That way you know where piston turning knob should be before inserting piston back to screw-unit. In most of pens piston turning knob needs to be screwed in some amount before inserting the piston. You can also try fiddle with assembly to get it right position, if you forget to mark it. I normally just take good picture with my phone, and that's enough for reference the place.