ASA Nauka's Design Quirk

[HartGummi]

 

In an ASA Nauka the cap threads are right at the front so the user must uncap the pen via torque transmitted through the barrel threads (highlighted in red). If you have capped the pen very tightly then it is possible that you could accidentally unscrew the barrel while trying to uncap the pen.

 

I paid attention to this quirk only recently when I came close to accidentally opening the barrel while it was full of ink. 

 

As the user below said, the cap threads right at the front are the most important feature of this pen so they cannot be moved. However machining the barrel threads to a higher pitch than the cap threads should eliminate the problem.

 

 

 

[BlueJ]

The threads on the Nauka are at the front of the section not to make machining easier, but to make the pen as comfortable to hold as possible. The Nauka wouldn't be the Nauka without this feature, in my opinion.

 

It frequently happens that trying to uncap this pen results in the section starting to unscrew. The solution is to grip the pen firmly at the part of the section that projects beyond the cap, then turn the cap. This is of course especially important when using the pen as an eyedropper.

[Dimy]

Ho thats a quirk for sure. The above solution looks good enough, the next I can think is to tighten it a bit less maybe.

 

From machining front, how about turning the threads of barrel and cap in opposite directions, that should prevent the issue when opening the cap, although overtightened when closing might cause same issue but that should be theoretically too tight anyway.

[HartGummi]

48 minutes ago, Dimy said:

From machining front, how about turning the threads of barrel and cap in opposite directions,

You could unscrew the barrel unintentionally when you tighten the cap of such a design. It will solve one problem but create another.

Aha, ninjaed:

although overtightened when closing might cause same issue but that should be theoretically too tight anyway.

 

[Dimy]

1 hour ago, HartGummi said:

You could unscrew the barrel unintentionally when you tighten the cap of such a design. It will solve one problem but create another.

Aha, ninjaed:

 

 

 

yup that's why I said that it might become a issue as well...

[BrassRatt]

Weren't some front-threaded pens made with left-hand section-to-barrel threading?  I forget the brands ... pre-ballpoint era. 

[hariharan]

On 1/10/2021 at 12:56 AM, HartGummi said:

 

In an ASA Nauka the cap threads are right at the front so the user must uncap the pen via torque transmitted through the barrel threads (highlighted in red). If you have capped the pen very tightly then it is possible that you could accidentally unscrew the barrel while trying to uncap the pen.

 

I paid attention to this quirk only recently when I came close to accidentally opening the barrel while it was full of ink. 

 

As the user below said, the cap threads right at the front are the most important feature of this pen so they cannot be moved. However machining the barrel threads to a higher pitch than the cap threads should eliminate the problem.

 

 

 

 

The above solution is a classic mechanics problem. of increasing the shear stress for barrel compared to the cap. The pitch, angle of the thread or even the depth can be varied... All we need is to ensure the shear stress in barrel should be more than cap by a certain factor. 

[hari317]

On this pen, the very purpose of the exposed section length which extends beyond the cap lip is to provide some space for the user to grip the section to unscrew the cap. This exposed length can be tweaked and customised, there are tradeoffs. 

 

 

[Manofadventure]

Am I the only one who feels that the Nauka design is a perfect stepping stone in evolution towards a safety eyedropper?

The cap threads at the very end of the section is a dead ringer for any Waterman pattern safety. Now, if someone mechanically inclined could design and incorporate a helical extension rod to be propelled from the barrel end......

[HartGummi]

26 minutes ago, Manofadventure said:

Am I the only one who feels that the Nauka design is a perfect stepping stone in evolution towards a safety eyedropper?

Instead of making just a safety pen perhaps it should be extended to a capless design ala Lamy Dialog 3.

Add a cutoff to a retractable pen and we are halfway there. If only somebody could think of an effective yet simple seal to stop the nib from drying...

[Rewpert]

I have had a Nauka model pen on my desk for several years now and I have never had a problem with accidentally the barrel unscrewing when I uncap it. As Hari says, there is plenty of room to grip the 'section' below the cap. I cannot ever imagine that element of the design being a problem in the real world.

[Kalikrates]

It can happen in the real world. It has happened to me today, I screwed the cap too tight (I have the, maybe questionable, habit of doing that to prevent ink from drying if I don't use a pen for some time) and now the barrel unscrews and the cap is stuck to the section. It won't come out (I can't get a very good grip on the part of the section that sticks out of the cap) so I'll probably need a hair dryer to loosen the threads.

 

Still love the Nauka, though. Probably it's just a matter of not screwing the cap too tight. I'll take it as a lesson for the future.

[hari317]

3 minutes ago, Kalikrates said:

It can happen in the real world. It has happened to me today, I screwed the cap too tight (I have the, maybe questionable, habit of doing that to prevent ink from drying if I don't use a pen for some time) and now the barrel unscrews and the cap is stuck to the section. It won't come out (I can't get a very good grip on the part of the section that sticks out of the cap) so I'll probably need a hair dryer to loosen the threads.

 

Still love the Nauka, though. Probably it's just a matter of not screwing the cap too tight. I'll take it as a lesson for the future.

Just use a pair of latex hand  gloves as a gripping sheet to get a good grip on the cap and section and unscrew. HTH. 

[sansenri]

I do agree with BlueJ, the Nauka is an admirable pen due to this special feature of the threads at the front of the section, leaving a wonderfully thread free, step free section and barrel!  There aren't many like this, and I find this to be a very desirable feature.