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Kaweco: Mini Piston Or Squeeze Converter


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#21 KaB

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Posted 09 March 2019 - 08:13

So, as OP, let me give an update.

Taking into account all suggestions, I ordered a BRASS sport with EF nib, piston converter and orange cartridges.

Up till now, I've been using the pen with the blue cartridge that came with it. 

1. the EF nib is a joy to write with. It really IS extra fine. And it's smooth. 

2. very reliable ink flow. I can do a crossword puzzle, ponder over some word for considerable time with the pen open and it'll write right away.

3. Thanks to the EF, the ink capacity is less of an issue. I'm still using the first blue cartridge

4. therefore: no news on the converter yet. I'll have to finish this cartridge first and then I'll come back to that

 

Thanks for sharing your experiences and suggestions!


fpn_kab_tsuki_yo_most_boring_212x150.gif  Current rotation: home: Lamy Al-star 1.5, GvFC Moss Green; Lamy Vista 1.1, Diamine Oxblood; Sheaffer Touchdown 0.6, Sailor Kin-Mokusei

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#22 TheDutchGuy

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Posted 09 March 2019 - 08:24

Good to hear that you like the pen! May it serve you as well as mine serves me. My AL Sport is always with me, we're inseparable.

fpn_1552119766__91e00ad0-bbee-4c97-a1fb-

#23 txomsy

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Posted 27 March 2019 - 16:36

For the AL stonewashed sport:

- squeeze converter

The reason is that the piston converter is too long, and you'll need to move the piston when closing the body, ejecting some ink, which makes it prone to messing unless you are careful after loading to replace the body with the nib over the ink bottle. That said, I own both a blue and a black stonewahed AL sports and both are with the piston converter (I also have squeeze converters but prefer the piston, as mentioned the squeeze is prone to staining and soon looks less good, you see less and is more difficult to tell how well it has filled).

 

For the Brass sport and Liliput

- Piston converter

I find it more convenient, none of these two had issues with converter length, and I do not need much ink capacity as I do not write that much (I do not mind re-inking somewhat more often). The squeeze converters might be just as nice if they didn't stain. I have had no issues with converter leaking, but rather the opposite, one of them is now starting to offer some resistance to movement -probably I need to clean it better- so mine are rather on the side of tight fit. At the beginning I had some issues with them leaking because I hadn't pushed them completely in, it took me a while to realize that this was the problem and not loose fitting. After I made sure they were correctly fitted, no more issues any longer.

 

For any:

- Cartridge and syringe. That's what I've been doing for decades and always works. As with converters, you need to ensure you push fully the cartridge or it may be left loose and make a mess. But while you need put the converter right only once, you need to be careful with the cartridge each time you refill. A minor issue is that with use, cartridges may end up finally being loose at the connection and you may need to replace them by a new one, but that's not expensive.



#24 Misfit

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Posted 08 June 2019 - 23:24

Good to hear that you like the pen! May it serve you as well as mine serves me. My AL Sport is always with me, we're inseparable.

fpn_1552119766__91e00ad0-bbee-4c97-a1fb-


I love that you have a pen that goes with you everywhere. I lack that connection to one pen, but would like to have that.
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#25 fountainbel

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Posted 18 June 2019 - 13:40

Hi Kaweco fans !

I’m intrigued after reading your unhappy comments on the Kaweco Sport “pinch" and “piston" convertors.
I don’t own a Kaweco sport , but I think it should be possible to make a bulb filler which can hold a serious amount of ink.
Attached a sketch showing the principle I have in mind.
The bulb  should be squeezed 5- 6 times to get a full ink sac over the breather tube.
One can stop  squeezing the bulb when no air is coming out in the ink bottle.
To make a prototype I would need the 5  missing dimensions mentioned on the sketch, being:
1- Diameter "d” : The exact diameter of the convertor bore, or better: the exact diameter of the nipple on which the convertor is seated.
2- Diameter”D” : The external diameter  of the convertor nipple.
3- Diameter “D1 : The external diameter of the convertor , or even better :the maximum diameter which would fit in the barrel bore.
4- Length “l” : The length of the reduced part of the convertor nipple.
5- Length “L” : The maximum length of the convertor to fit inside the barrel.
I”ll make a prototype for evaluation - free of charge -  for the first  member who will give me the missing dimensions.
Looking forward to get the missing dimensions !
Best regards,
Francis
2019-06-18%2011.07.16.jpg
 
 
 


#26 txomsy

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Posted 18 June 2019 - 15:17

That is true. And there are several examples around on similar solution: you get a cartridge, cut it, fit a large (as much as the body allows) sac and fix it with shellac. Much like any sac filled pen from yonder.

 

What I would rather see is a twist converter working on the principles of Arqhimedes' screw: turning a knob connected to the screw would move up and down the piston to fill/empty the converter. This would do away with waste space needed for the axis when the piston goes up. What it would move up and down would be the piston, and the piston by creating vacuum, would draw the ink.

 

Archimedes_screw.JPG

 

Why? Because then you do not need any space for the piston axis, which is what makes current converters waste half of the available space. That would mean (almost) doubling the capacity of any converter size.

 

Why not? One may link the screw to the twister, so that as you twist it, the screw turns. For it to make the piston go up and down you would need at least one "guide" on the wall of the converter that fixes the piston orientation, so that when the screw turns it forces the piston to move. This requires a container that is not a simple, straight tube. And the piston should have a shaped, non-cylindrical hole adapted to the screw (like a nut). I can see why with old machinery and design media this would be discarded in the old times. But this should be easily doable with modern technology; yet, properly producing it would likely require new machinery and to justify the cost of this machinery one would need to guarantee a large enough demand, which with modern (lack of) use of refillable writing instruments may be difficult to justify,

 

On the other hand, plastic is becoming an ever larger concern. Fountain pens are a great solution to reduce the huge amount of "bic" and bic-like plastic pens being discarded and thrown away every year. And converters to reduce use of cartridges. A more conscious, waste-reducing society should reconsider going back to refillable devices like fountain pens, specially now that carbon copy paper is no longer needed. That makes for a strong argument to address contamination-conscious users and appeal them to the FP world. So may be at one point it may make sense to redesign converters to profit from new advances in technology.

 

Sorta, something like this very gross draft:

fpn_1560870706__archimedes-screw-piston.

 

 

Note that many current converters do use a screw but it attached to the piston and rotation draws -by a similar principle- the screw axis and piston up and down. What I propose is that the screw is attached to the know and not the piston, so that it is the piston that "screws in/up - out/down" when the knob (and attached screw) is turned. Just as current converters need a fixed nut to move up/down the screw/piston unit. the piston would act as a nut, fixed in the X-Z plane by the "tongue" in bass relief in the inner part of the sleeve cylinder and would be free to move on the Y direction (up/down) as the screw is turned.

 

Come to think of it, an easier design would be to have an hexagonal reservoir (instead of a cylindrical one as it is now) so that the piston would be actually a normal nut and the axis a bolt, this would only require a (more or less) normal/standard nut and bolt/screw and would not require a specially shaped cylinder with an inner tongue, which may be more prone to failure. We see a similar design in many mechanical items indeed.


Edited by txomsy, 18 June 2019 - 15:26.


#27 txomsy

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Posted 18 June 2019 - 15:51

Thinking of it, another benefit might be that the hole unit might be easy to assemble/disassemble and maintain/repair. With an hexagonal reservoir additional refinements would be feasible.... maybe I should have filled for a patent on this. Well, too late, now there is prior art publicly available (the previous message  :) )

 

One day I'll come up with enough time and the required tools... dreaming awake... oh, well!



#28 fountainbel

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Posted 18 June 2019 - 18:05

Thinking of it, another benefit might be that the hole unit might be easy to assemble/disassemble and maintain/repair. With an hexagonal reservoir additional refinements would be feasible.... maybe I should have filled for a patent on this. Well, too late, now there is prior art publicly available (the previous message  :) )

 

One day I'll come up with enough time and the required tools... dreaming awake... oh, well!

 

Hi txomsy,

Thanks for sharing your interesting idea !

However there are some  practical issues which you should consider in my opinion:

- You will need a seal ( O ring) in the piston with will make the piston wider.

- Given the necessary guiding ridge you've provided installing a positive piston seal will be very difficult

- Ink leakage over the lead screw will be a problem in my opinion.

- The turning knob should also be centered and  axially fixed in the body of the convertor in my opinion.

- Making an hexagon  convertor body would also make it considerably more difficult to obtain a proper piston sealing.

Just my two Euro cents….

Best ,

Francis 



#29 Honeybadgers

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Posted 19 June 2019 - 00:09

I have no issues with the mini piston, and despite all people complaints about the squeeze, I have two and they work just fine (one is the only way I could get a converter in a an ensso minimilistica) 

 

I do have a preferred method, however, of just using sacs for lever fill pens, and making a custom length squeeze filler that fits the length of the pen it's going in. I had to improvise one for my cross spire, which only takes the proprietary thin cross cartridges, which I don't know how long they'll still be made since the only pen that used them is discontinued. I just shortened one, shellac'd a sac to it in the entire length of the pen's barrel, and now I have a pretty immense amount of ink in that pen, far more than a cartridge.

 

I don't like cartridges and would not use a kaweco sport if I had only cartridges.

 

But, to be honest, Don't buy the kaweco sport. Just get a delike alpha in brass, aluminum or resin for the price of a kaweco sport. it's about a centimeter longer and can accommodate a proper converter, INCLUDES a converter, and includes a clip. The brass one can be polished up with some light sandpaper to remove the lacquer and give you that nice patina for a pittance.
 

 

My delike alpha has saved a person's life when I had to use it as an improvised glass breaker on an accident scene. It also takes a TON of different nibs. I put an EF eversharp 14k manifold in it.

 

fpn_1560903412__20180920_220118.jpg


Edited by Honeybadgers, 19 June 2019 - 00:17.

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#30 Honeybadgers

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Posted 19 June 2019 - 00:12

Thinking of it, another benefit might be that the hole unit might be easy to assemble/disassemble and maintain/repair. With an hexagonal reservoir additional refinements would be feasible.... maybe I should have filled for a patent on this. Well, too late, now there is prior art publicly available (the previous message  :) )

 

One day I'll come up with enough time and the required tools... dreaming awake... oh, well!

 

You'd run into difficulties with the seal between the piston and the rod itself. It would need to be smooth enough for the piston to move without wobbling (could be done by just giving it a little 1mm tube section but unless there was a good seal around it, you'd have problems drawing ink up. And if the whole cartridge was sealed, you'd run into a pressure differential that wouldn't work either.

 

In theory, it's a great idea, but I don't know how I'd get that piston to seal against the rod well enough to be reliable.


Selling a boatload of restored, fairly rare, vintage Japanese gold nib pens, click here to see (more added as I finish restoring them)


#31 KaB

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Posted 19 June 2019 - 16:51

Hi all (and Fountainbel especially: hoi Francis)

 

As OP, let me give yet another update:

(if you want the full story: http://www.fountainp...rglue-solve-it/ )

 

I fully enjoy the Kaweco BRASS sport with EF nib. As mentioned before: sturdy pen (can have a lot), nice nib. Having selected an EF nib solves all my quantity-of-ink issues.

However: both the converter and the Kaweco cartridges don't stick firmly to the nipple. They tend to get unstuck and loose ink. Yes, first time maybe 'cause the nib unit wasn't fully skrewed in. But after that, the problem repeated.

 

on the 'will superglue solve it' thread, you'll discover some great suggestions, one of which I adopted. And it hasn't failed me yet:

2 twists of electricitytape and the converter is nicely stuck, leaving a small part of an ink window.

 

(I'm trying to post a pic but somehow that doesn't work for me anymore. Not a pic on flickr, neither a pic uploaded here   :( )


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#32 KaB

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Posted 19 June 2019 - 16:53

So I'm very charmed by your offer Francis. But it sounds to me that solution is focused on maximising the ink capacity. Which is not really my problem. And I might end up with my original problem again: a nipple too short to decently keep a converter in place.

 

Or did I totally misunderstand your aim and drawing?


fpn_kab_tsuki_yo_most_boring_212x150.gif  Current rotation: home: Lamy Al-star 1.5, GvFC Moss Green; Lamy Vista 1.1, Diamine Oxblood; Sheaffer Touchdown 0.6, Sailor Kin-Mokusei

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#33 Tweel

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Posted 19 June 2019 - 17:46

Hi Francis,

 

Here's my attempt to supply the measurements you want, as exactly as I could with a cheap digital caliper.  I have an AL Sport "Raw", and one of the newer bulb-style squeeze converters.

 

 

1- Diameter "d” : The exact diameter of the convertor bore, or better: the exact diameter of the nipple on which the convertor is seated.

 

  • Converter bore: 2.26 mm.  Nipple diameter: 2.35 mm.

 

2- Diameter”D” : The external diameter  of the convertor nipple.
 
  • 4.35 mm.
 
3- Diameter “D1 : The external diameter of the convertor , or even better :the maximum diameter which would fit in the barrel bore.
 
  • I measured the swaged metal sleeve that holds the sac to the plastic nipple, as this is the largest-diameter part of the squeeze converter.  7.05 mm.  Barrel bore: 9.03 mm.
 
4- Length “l” : The length of the reduced part of the convertor nipple.
 
  • 2.02 mm.
 
5- Length “L” : The maximum length of the convertor to fit inside the barrel.
 
  • I was a little unclear on what exactly you were looking for here.  However, 7.67 mm of the converter fits down into the well in the top of the section.  Beyond that, there is 37.58 mm of the converter's length free inside the barrel.  The end wall at the top of the barrel seems to be quite thick, providing less interior space than I expected.  Beyond the top of the section, there is an interior barrel depth of 39.27 mm available.

Edited by Tweel, 19 June 2019 - 17:47.

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#34 fountainbel

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Posted 19 June 2019 - 19:20

Excellent Tweel, thanks  !

By the end of next week I'll ship you the convertor for evaluation.

Please send me your address with PM

Regards,

Francis 



#35 Tweel

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Posted 19 June 2019 - 21:13

Thanks Francis!  I'm looking forward to it.


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#36 fountainbel

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Posted 22 June 2019 - 17:29



Thanks Francis!  I'm looking forward to it.

 

Hi Tweel & Kaweco fans !

As promised to "Tweel", I’ve just finished his alternative convertor for the Kaweco Sport.
The new “Bulb" squeezing convertor can be filled to a volume of 1.1/1.2Ml.
The convertor is completely filled in 8 squeezing operations.
Allowing a larger volume displacement  when squeezing the bulb I’ve flattened the breather tube 
I’m a little disappointed, since I was hoping for a larger volume.
However the barrel bore diameter and even more the depth of the barrel bore were the limiting factors.
As i understand the barrel bore could be made deeper, but since I don’t own a Kaweco sport I c’ant determine how much the barrel bore can de deepened and the convertor could be made longer.
Note on the picture the convertor is mounted on a Bock size 6 nib unit , as far as I know Kaweco uses Bock nib units, Hope this is right?
The convertor will also fit on a Bock size 5 nib unit which is as far as I can see used on the Kaweco Sport.
I’ll ship the convertor to Tweel on Monday and look forward reading his evaluation test !
Best regards,
Francis
PS:
1-Please note that I’m not interested in making more of these convertors,
The drawing is attached, so feel free to make your own when interested !
2- For Tweel : Could your please check the dimensions and confirm the convertor will fit in your pen? Let me know If the convertor could be longer,
I can stilll elongate the bulb so the ink intake would increase  !
 
edited-image_21.png

Edited by fountainbel, 22 June 2019 - 19:40.


#37 TheDutchGuy

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Posted 22 June 2019 - 17:51

Amazing work, very inspiring!

#38 Tweel

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Posted 22 June 2019 - 22:22

Note on the picture the convertor is mounted on a Bock size 6 nib unit , as far as I know Kaweco uses Bock nib units, Hope this is right?

The convertor will also fit on a Bock size 5 nib unit which is as far as I can see used on the Kaweco Sport.
 
Yes, it uses a Bock 060 nib unit with a #5 nib.
 
2- For Tweel : Could your please check the dimensions and confirm the convertor will fit in your pen? Let me know If the convertor could be longer,
I can stilll elongate the bulb so the ink intake would increase  !
 
I have to admit I'm having a little trouble interpreting some of the dimensions in your drawing (my fault, and not helped by a current migraine!).  However, from what I can see the dimensions look OK with a conservative margin... except possibly for one.  The reduced part, between the nipple and the main body, is 7.3 mm in diameter?  If so, I'm afraid it might not fit into the section -- the section's internal diameter, where the converter fits down inside, is something like 6.85 mm.
 
The stock converter is the same length as yours, and there seems to be something on the order of 1 mm more of depth in the barrel, so it's OK as-is.
 
I like your mini-aerometric design, and thank you for letting me be the guinea pig for your curiosity in this Kaweco converter matter!
 

fpn_1375035941__postcard_swap.png * * * "Don't neglect to write me several times from different places when you may."
-- John Purdue (1863)

 


#39 fountainbel

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Posted 23 June 2019 - 09:16

Hi Tweel, 

Thanks for your feedback !

I've adapted the diameter of the reduced part between the nipple and the main body to 6.5 mm, over a length of 7mm starting from the front of the nipple, hope this will be OK?

I'll ship your convertor tomorrow.

Best regards,

Francis 

 

Note on the picture the convertor is mounted on a Bock size 6 nib unit , as far as I know Kaweco uses Bock nib units, Hope this is right?

The convertor will also fit on a Bock size 5 nib unit which is as far as I can see used on the Kaweco Sport.
 
Yes, it uses a Bock 060 nib unit with a #5 nib.
 
2- For Tweel : Could your please check the dimensions and confirm the convertor will fit in your pen? Let me know If the convertor could be longer,
I can stilll elongate the bulb so the ink intake would increase  !
 
I have to admit I'm having a little trouble interpreting some of the dimensions in your drawing (my fault, and not helped by a current migraine!).  However, from what I can see the dimensions look OK with a conservative margin... except possibly for one.  The reduced part, between the nipple and the main body, is 7.3 mm in diameter?  If so, I'm afraid it might not fit into the section -- the section's internal diameter, where the converter fits down inside, is something like 6.85 mm.
 
The stock converter is the same length as yours, and there seems to be something on the order of 1 mm more of depth in the barrel, so it's OK as-is.
 
I like your mini-aerometric design, and thank you for letting me be the guinea pig for your curiosity in this Kaweco converter matter!
 

 



#40 Tweel

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Posted 23 June 2019 - 16:18

You're welcome Francis, and thank you!  PM sent re various points.


fpn_1375035941__postcard_swap.png * * * "Don't neglect to write me several times from different places when you may."
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