Osmiroid FP's were standard issue when I was a schoolboy in England in the 1960's. Using ballpoints (biros) was considered insulting by teachers and were not acceptable during exams. Writing lines (a punishment) could only be done with FP's.

I have a junk example of each. The 65: petrified sac and shrunken-diameter cap. The 75: piston and seals need rebuilding, cap end is missing, as is the clip, and the (white) pen acquired a blue tint in the ultrasound tank.

As a start, how do you disassemble them? The 65 section is not moving off the barrel yet. The 75 doesn't seem to be designed for servicing.

Not as urgent as it was before I discovered Esties can carry the Osmiroid nibs.

65-- I've just rechecked mine; I've got an earlier round-top and a later oblique-top, and in both cases the section unscrews without a great struggle with the same twist direction as the cap.

75-- It sure doesn't give the impression of "repairable", does it? The one I've currently got is in relatively good shape, and rather than dismantle it I've simple relubricated the seal by taking out the point and thrusting some of the appropriate silicone grease into the cavity with a tooth-pick, then working the piston a few times (if you can warm it so that the grease is looser, it helps). If dismantling is required, so are NERVES OF STEEL, or at least some reasonable durable material; run the piston all the way down, then keep turning the knob with ever-increasing force. It will eventually drive itself off the piston shaft and then unscrew from the body. Once it's out of the way, you can drive the piston out through the tail of the barrel for full inspection-- I used the blunt end of a bamboo skewer as my ramrod. Putting it back together just reverses the effort-- prod the piston right down in the chamber, and screw down the knob.

Thank you, Ernst, you've given me the confidence to unscrew my 65's, worked with a lot of finger force using an inner tube for grip.

Now the 75...
Unscrewing the rear of the barrel moves the piston towards the nib. The jerky motion suggests lubing might do some good. I put on lots of force to continue unscrewing, and felt the entire barrel twisting, but the knob will not turn out of the barrel. It also did not suffer destruction, and the piston can still be retracted when screwing the rear knob back tight to the barrel.

Has anyone successfuly dismantled an Osmiroid 75?

Hi Ernst!

Your post is very helpful. Thank you!

But I have a question or two... My Osmiroid 75 pen leaks & you mentioned "appropriate silicone grease", can I ask a brand or more details on what/where to buy the silicone?

It seems to leak at the top "nib area" & bottom "twister end", when turning the twister it leaks ink slightly on my fingers. And the "top nib area" leaks too much ink onto the nib.

Could I use the silicone on both ends of the pen and how?

Any insight would be greatly appreciated. It is a lovely pen &
I really want to USE it... (that is- without the blue fingers I presently have!)

Pen Pixie

No idea on brand names for grease-- I got my tiny tub of it from Tryphon, I understand the true pure stuff can also be had from Scuba shops, I've seen it posted for sale at Martin's Pens and I expect it can be got from Pendemonium as well.

I imagine one could apply a little grease to the threads of the point to act as a bit of a safety seal.

I'd like to hear from anyone else if RRRR's problem with hauling out the piston has a different solution than my brute-force suggestion. I have had a 75 apart in the manner I suggest previously, but I will admit that saying, "Just give 'er!" seems a little inelegant.

Ernst, I also have an Osmiroid 75 that looks BEYOND repair... The "twister" is very chewed up and stripped... I can pull the bottom part completely off but am "at a loss" at how to remove the piston.

If anyone knows how to pull the piston out of pen I could try it...

The twister is stripped and the piston doesn't seem to move at all. I have soaked it for days on end, it looks clean but no go. I bought it really cheap for pieces & experiments such as this!

Thanks for the help on the silicone!

Pen Pixie