Pelikan 400Nn Merz & Krell Piston Assembly

[stoen]

Hello,

I'd like to share a question about disassembling the piston mechanism on Pelikan 400NN Merz&Krell. I got one today, literally covered in dirt and dust. After few hours of soaking in lukewarm distilled water, I could easily take apart the nib assembly, the collar, the feed, clean and re-set the nib, put everything back together, ink it and write test it. To my surprise, I found it to be in mint condition, perhaps used once and set aside, than forgotten for 40 years.

The only thing I was afraid to mess with was taking apart the piston assembly. It isn't a matter of whether I really needed it, I prefer learning how to do it. I understand it is right-threaded (=normal-threaded), but I see no clue for unscrewing it.

Is there someone who could give me detailed instructions on how to do it?

Should I turn it past the point of having pushed the piston all the way down? I see no dried ink traces on the "wrong side of the piston". These pens are rather scarce, so I haven't done this before and I am afraid of applying force which could break the differential system on this beautiful pen. Any expert hint will be more than welcome.

 

Thanks in advance!

Edited February 28, 2020 by stoen

[Tweel]

I'm operating blind, since I don't have a 400nn, M&K or not. However, going by the construction of modern Pelikans, and without doing any harm: When you turn the piston knob in the "expelling" direction (counter-clockwise on your pen?), the knob should lift away from the barrel a little. When that is done, and you look at the collar under the knob and against the barrel end, do you see two flat faces on opposite sides of that ring?

[stoen]

I'm operating blind, since I don't have a 400nn, M&K or not.

Thanks for your effort in trying to contribute. Unfortunately, educated guessing would not help here (I wish it could); the 400NN M&K is a vintage pen, also too specific, so nothing you have suggested really applies here. The round (cylindrical) underside of the knob extends into the barrel, no flat faces (parallel sides) or notches appear. The collar cannot even be reached (if there is one at all).

Thanks, nevertheless.

Edited February 28, 2020 by stoen

[Tweel]

Okay, someone will be along who knows how to unscrew it.

[joss]

The M&K piston mechanism is indeed threaded into the barrel and it is a normal (not reversed) thread.

 

The way to proceed to remove the piston mechanism is slightly nerve wrecking. Keep on turning the piston knob to the left until the piston is in its "fully down" position. Normally you would stop there when you want to fill the pen with ink. But if you want to remove the piston mechanism you have to 'force' the piston knob further to the left. That is the nerve wrecking part but it should unscrew the piston mechanism from the barrel.

 

I would first soak the pen in warmish water before proceeding with the above.

[stoen]

But if you want to remove the piston mechanism you have to 'force' the piston knob further to the left. That is the nerve wrecking part but it should unscrew the piston mechanism from the barrel.

 

I would first soak the pen in warmish water before proceeding with the above.

 

Thanks, @joss, I have already tried doing exactly the same, after hours of soaking in warmish distilled water I was surprised at the amount of force I had to apply only to see nothing happen. There I gave up for fear of breaking the pen and posted this topic hoping someone with experience in repairing M&K 400NN would be so kind to give me a bit of advice.

 

Have you done this before? Is there an extra movement (such as pushing or pulling) to be applied while unscrewing?

I am a patient and skilfull person, having succesfully repaired a number of early vintage Pelikans. Yet, I havent come across this one so far. That is my reason for caution.

Edited February 28, 2020 by stoen

[joss]

Have you done this before? Is there an extra movement (such as pushing or pulling) to be applied while unscrewing?

I am a patient and skilfull person, having succesfully repaired a number of early vintage Pelikans. Yet, I havent come across this one so far. That is my reason for caution.

I have done this before and there is no extra movement involved, I would not push or pull. It is good to be cautious because further unscrewing the piston knob on a fully extended piston will also force the threaded mechanism in the upwards direction while you just want the mechanism to rotate. That's why it is a nerve wrecking procedure. The problem with old pens is that you never know what a previous owner may have done to the pen (eventually shellacked the piston threads or so).

 

You may try with the additional help of an ultrasonic bath. But as you already mentioned, there might be no need to remove the mechanism if everything works fine.

[Erik Dalton]

I have done this before and there is no extra movement involved, I would not push or pull. It is good to be cautious because further unscrewing the piston knob on a fully extended piston will also force the threaded mechanism in the upwards direction while you just want the mechanism to rotate. That's why it is a nerve wrecking procedure. The problem with old pens is that you never know what a previous owner may have done to the pen (eventually shellacked the piston threads or so).

 

You may try with the additional help of an ultrasonic bath. But as you already mentioned, there might be no need to remove the mechanism if everything works fine.

 

+1....I agree with Joss, if its working, not leaking, it might be wise to leave it be. If the piston seems a bit stiff, you could go in from the front and lubricate the piston head with a tiny bit of silicone grease on the end of a toothpick. It doesn’t take much to get a big result.

As joss said, the thing with these old pens is that you are traveling blind without any knowledge of what previous owners have done to it. You can find some strange things when you open these pens.

While working on a Parker 51, i had a very difficult time getting the hood off. Turns out that the prior owner had glued it on with barge cement. what a mess. So my advice; You have a really nice pen there, if it’s not broke don’t try and fix it.

[stoen]

The problem with old pens is that you never know what a previous owner may have done to the pen (eventually shellacked the piston threads or so).

Thanks very much.

 

Of course one must cultivate reasonable fears against smart mistreatment by the former owner. It is part of the risk of resurrecting vintage pens. It is hard to overstress the importance of such a caution.

 

Yet, this one appears to have been used for no more than a week or so, then put aside full of ink, forgoten, and stored in a dusty basement for 45 years. It even had traces of the factory EF sticker on the barrel. Except for the dried ink in the barrel, the pen has absolutely no signs of having been used. Only traces of having been stored for years in a dusty place.

 

My only aim was asking about the full description of the legitimate take-apart / put-back-together procedure for the piston assembly. Thanks for the suggestions about ultrasonic bath.

 

All this will help me determine if the pen had been tampered with, which by all other signs does not appear having been so. I guess the short-time former user had better to do with it than screw-and-glue.

 

@Old Salt: Thanks for the words of wisdom and common sense. No need to worry about possible barge cement, toothpick, and silicon grease. Ive inspected the inner threads with strong through-light. No obvious signs of glue-abuse have been detected.

(-:

Edited February 29, 2020 by stoen

[Erik Dalton]

Sounds like you have it in hand now. Soon you’ll have it inked and writing away. Again nice find, good pen.

[stoen]

Again nice find, good pen.

Thanks, I couldnt agree more. It seems scarce to find nowadays, particularly in this condition, for a reasonable price. It is the first one I have spontanously come across in 20+ years.

It feels like the link between vintage and modern Pelikan classics I have been missing. Under modern I count those models beginning with M. Not a matter of wording, but rather of technology and writing features & properties. I know someone may object, but this is my way of understanding Pelikan pen evolution.

Edited February 29, 2020 by stoen

[sombrueil]

One of my favorites of the vintage Pelikans. These are real workhorse pens. My NN Tortoise is a pen I will have until I can write no longer.