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bobje

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Siamackz,

Great question. Vent hole placement is the variable I'm most focused on, and how this compares to previously successful falcon wing modification. Size of vent hole, exact position, shoulder width, etc. -- these are experiments for someone else. I am trying to determine if flexibility in an FPR nib can be improved by a vent hole or enlarged vent hole, and whether this mod can be performed by a layman with simple tools.

The breather hole effects the flexibility, sure, however there are other parameters which have a more substantial impact... position of scallops, material thickness, length of slit and the material itself

with kindness...

 

Amadeus W.
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TEST NO. 5 -- FPR NO. 6 FLEX NIB (VENT HOLE IN CENTER POSITION)

A. WRITING RESULTS AFTER MODIFYING FLEX NIB WITH 1/16 INCH VENT HOLE, DRILLED JUST BEHIND THE SHOULDER

Click pen with no. 6 FPR flex nib, 6.3 mm standard ebonite feed

This was an attempt to repeat Test No. 3 with more successful results. The vent-hole-modified flex nib provides line variation of approximately 3x, from a line width of about 0.5 mm to 1.5 mm, with less pressure, and provides a smooth writing experience. The nib never railroaded. However, ink delivery was too wet, and attempts to move the feed backward to reduce ink flow were only partly successful. A motorized hand drill was used to create the vent hole, which improved workmanship somewhat over previous attempts (Graphic 2).

CONCLUSIONS OF TEST NO. 5

Degree of flex is improved with less pressure, but an overly wet nib/feed assembly is difficult to control with any degree of consistency. This is essential in calligraphy. Drilling a hole along the channel of the FPR feed seems to encourage too much ink flow (Graphic 1). Using the stock feed from the standard Airmail Wality feed was extremely successful, however, when combined with a similarly modified flex nib in the Airmail Wality 71J.

Graphic 1

fpn_1500938117__handwriting-sample-test-

Graphic 2

fpn_1500854135__airmail-wality-flex-nib-

ahm... placing the hole at this point should not have much effect, the long slit's impact is far stronger.

The feed you use: where is its air canal? If it's on the top, with the ink capillary then too much air would enter and increase the ink flow. Swapping the feed with one with the air canal on the opposite side would rectify this problem

with kindness...

 

Amadeus W.
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Mauricio, I admit that my grasp of physics may be very basic, but what you write about forces and pressure just doesn't seem to make much sense. I guess you take metaphysics for physics.

:lticaptd: :rolleyes: :blush:

with kindness...

 

Amadeus W.
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Amadeus, you are correct as expected, that placement of a hole made no difference. It seems obvious now.

 

The air canal is on the top, and it definitely admitted too much air. These feeds don't have an air canal on the bottom, and I dont know if one could be created there, in addition, or in place of, the one on top.

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Amadeus, you are correct as expected, that placement of a hole made no difference. It seems obvious now.

 

The air canal is on the top, and it definitely admitted too much air. These feeds don't have an air canal on the bottom, and I dont know if one could be created there, in addition, or in place of, the one on top.

Oooh, ahm... best would be if you could find a fitting feed with the air canal on the bottom. Creating on there? Tricky because it's not only the air canal, it's also the air inlet regulator which would need to be moved, and the air canal on the top needs to be closed without interfering with the ink capillary, capillaries.

 

I am amazed about the mixing and matching you guys do and with so much success. When I remember the effects of changing minute details of the feed on ink flow and other behaviours during my time of fountain pen ingeneering... amazing.

Edited by PenIngeneer

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Amadeus W.
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Stimulated by this forum, I have started writing an article for my website, where I want to look more into the mechanical and functional aspects of flex-nibs. I struggle with coming up with definitions for the various degrees of flex :blush: . Here is what I have written about this, which includes what I have learned from this forum B) :

 

> So, where is the demarcation between flex and nail? I suggest it being a question of intention and of degree. I mean: had the nib been designed for being a normal nib or had it been designed to perform as a flex nib.

 

> The degree? Some people consider a nib to be a flex nib when it can spread its tines repeatably by one millimeter. Some others want it to spread by four millimeter.

 

> Some suggest it is the ratio between the line width when applying little or no pressure and the line width at a comfortable or maximal, repeatable pressure. A variation from 0.2mm to 1.2mm would result in a ratio of 6, also noted as 6X. Some flex nibs achieve a ratio of 20X.

 

> The last suggestions appeals to me, the ingeneer. It offers a measurable, repeatable and therefore reliable method. However, somehow I feel the force required to achieve a certain ratio must be included, too.

 

§

 

 

I also wonder if there is a standardised naming for the flex-ability or flex-characteristics :rolleyes: . I have heard of nails and wet noodles, both very descriptive and fun terms. Not good for technical analysis :unsure: . Help is appreciated.

 

§

 

 

 

If there is anyone in this forum who does not want information of their posts to be used in my article, please tell me. No problemo! :)

Edited by PenIngeneer

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Amadeus W.
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Oooh, ahm... best would be if you could find a fitting feed with the air canal on the bottom. Creating on there? Tricky because it's not only the air canal, it's also the air inlet regulator which would need to be moved, and the air canal on the top needs to be closed without interfering with the ink capillary, capillaries.

 

I've found that making a feed for a "D" shaped section is more of a challenge than making one for a round one.

(The Jowo has a flat on the bottom)

 

I made a couple that leak near the corners of the "D" and it ended up being a good thing.

Mine were all slightly cork shaped and I'd move the feed in or out until I could get the right amount of leaking.

It would write wet for a little bit and then become a bottom vent.

The pen would work perfectly until I had to fill it up again and then I'd have to "reset it" by touching the bottom of the feed to a paper towel.

 

This worked for the Leonardt Principal & the Zebra-G

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I also wonder if there is a standardised naming for the flex-ability or flex-characteristics :rolleyes: . I have heard of nails and wet noodles, both very descriptive and fun terms. Not good for technical analysis :unsure: . Help is appreciated.

 

 

I don't think there is a standardized naming system, but the most often I encounter the soft-semi/moderately flex-flexible-very flexible gradation. Different sellers offer their own naming like Gary Lehrer (gopens.com): a touch/tad of flex, flexible, extra-flexible and triple flexible.

 

Then, there are the most popular baroque systems like Mauricio's (http://vintagepensblog.blogspot.co.uk/2015/07/measuring-nib-flexibility.html?m=1) and Bo Bo Olsen's. Unfortunately they rely on a experienced user's experience and in this aspect are rather esoteric - 'you can't know and talk about flex without experiencing hundreds of real flexible nibs or sold by the most proficient in flex sellers like me'. However, I think that Bo Bo Olsen's one, although confusing, is not bad at all but needs some empirical data to make it work.

 

The most interesting work on defining and grading flexibility in my opinion was relatively recently undertaken by Croma (https://www.fountainpennetwork.com/forum/topic/291773-rigidity-index-a-simple-method-to-evaluate-the-flexibility-of-a-nib/) and David Nishimura: http://vintagepensblog.blogspot.co.uk/2015/07/measuring-nib-flexibility.html?m=1, https://www.fountainpennetwork.com/forum/topic/293267-measuring-flexibility-a-proposal/.

 

I use weighing scales to understand behaviour and differences in my own nibs. Usually, for my personal use I employ the weight/pressure range between the initial tines opening and the maximum comfortable (moderate and seemingly safe) deflection to grade them. It's subjective and I still can't say whether a nib should be called semi or full flexible but it works for me. Also it shows patterns in nibs behaviour. For example, I have a number of vintage nibs of one producer and they can be divided in four different but well defined groups according to similar behaviour. This would suggest that they were made to several specific designs in a controlled way.

Edited by 7is
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Thank you for these insights, Peningeneer!

 

If we imagine looking at the tail end of the feed, are we concluding that a single ink channel at the 12 o'clock position, combined with a large vent hole, creates too much air/ink interchange? Would placing two smaller ink channels at something like 2 and 10 o'clock, avoiding the large vent hole at 12 o'clock, prevent the problem? And in the case of these ebonite feeds, is the single channel on top serving as both the air channel and the ink channel?

I would love to answer, but your description still allows many variations. Could you show us a photo?

with kindness...

 

Amadeus W.
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I don't think there is a standardized naming system, but the most often I encounter the soft-semi/moderately flex-flexible-very flexible gradation. Different sellers offer their own naming like Gary Lehrer (gopens.com): a touch/tad of flex, flexible, extra-flexible and triple flexible.

 

Then, there are the most popular baroque systems like Mauricio's (http://vintagepensblog.blogspot.co.uk/2015/07/measuring-nib-flexibility.html?m=1) and Bo Bo Olsen's. Unfortunately they rely on a experienced user's experience and in this aspect are rather esoteric - 'you can't know and talk about flex without experiencing hundreds of real flexible nibs or sold by the most proficient in flex sellers like me'. However, I think that Bo Bo Olsen's one, although confusing, is not bad at all but needs some empirical data to make it work.

 

The most interesting work on defining and grading flexibility in my opinion was relatively recently undertaken by Croma (https://www.fountainpennetwork.com/forum/topic/291773-rigidity-index-a-simple-method-to-evaluate-the-flexibility-of-a-nib/) and David Nishimura: http://vintagepensblog.blogspot.co.uk/2015/07/measuring-nib-flexibility.html?m=1, https://www.fountainpennetwork.com/forum/topic/293267-measuring-flexibility-a-proposal/.

 

I use weighing scales to understand behaviour and differences in my own nibs. Usually, for my personal use I employ the weight/pressure range between the initial tines opening and the maximum comfortable (moderate and seemingly safe) deflection to grade them. It's subjective and I still can't say whether a nib should be called semi or full flexible but it works for me. Also it shows patterns in nibs behaviour. For example,

 

I have a number of vintage nibs of one producer and they can be divided in four different but well defined groups according to similar behaviour. This would suggest that they were made to several specific designs in a controlled way.

Thanks for that. It's late over here and bed time -_- . I will investigate the links tomorrow.

 

I would love and come over and visit you and inspect you collection and learn about the way you sorted them. I am confident that we could work something out :rolleyes: . What's the next best thing to do?

with kindness...

 

Amadeus W.
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I've found that making a feed for a "D" shaped section is more of a challenge than making one for a round one.

(The Jowo has a flat on the bottom)

 

I made a couple that leak near the corners of the "D" and it ended up being a good thing.

Mine were all slightly cork shaped and I'd move the feed in or out until I could get the right amount of leaking.

It would write wet for a little bit and then become a bottom vent.

The pen would work perfectly until I had to fill it up again and then I'd have to "reset it" by touching the bottom of the feed to a paper towel.

 

This worked for the Leonardt Principal & the Zebra-G

Have you tried to drill out the D shape to make the opening round?

with kindness...

 

Amadeus W.
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Amadeus, you will find David Nishimura's work useful. These ebonite feeds do not currently offer an option with an air inlet on the bottom, unfortunately. The only inlet is on the top.

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Wow, this is very sophisticated and I am impressed. Thank you for sharing your findings.

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Amadeus, you will find David Nishimura's work useful. These ebonite feeds do not currently offer an option with an air inlet on the bottom, unfortunately. The only inlet is on the top.

Thanks Bobje. I had a look and found many articles. Would you tell me what you are referring to?

with kindness...

 

Amadeus W.
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Reviews and articles on Fountain Pen Network

 

CHINA, JAPAN, AND INDIA

Hua Hong Blue Belter | Penbbs 456 | Stationery | ASA Nauka in Dartmoor and Ebonite | ASA Azaadi | ASA Bheeshma | ASA Halwa | Ranga Model 8 and 8b | Ranga Emperor

ITALY AND THE UK

FILCAO Roxi | FILCAO Atlantica | Italix Churchman's Prescriptor

USA, INK, AND EXPERIMENTS

Bexley Prometheus | Route 54 Motor Oil | Black Swan in Icelandic Minty Bathwater | Robert Oster Aqua | Diamine Emerald Green | Mr. Pen Radiant Blue | Three Oysters Giwa | Flex Nib Modifications | Rollstoppers

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Thank you all for posting your work -- real scientists publish!

...and "mad nib scientist" sounds like a fun title :)

 

 

Introduction

 

I don't feel qualified to peer-review this thread's previously published work, so I've attempted to reproduce your results in an independent lab (my garage). I've also examined the suggestion of thinning the metal one of your peer reviewers mentioned, tho measuring the thickness of the reduction and thinning a consistent amount are beyond my available tooling and current ability.

 

 

Methods

 

I modified only untipped Noodler's flex nibs, to isolate the modifications as the only experimental variable (and because they are cheap). I tried several modifications:

  • cutting a horizontal slit at the widest point on wings
  • cutting a horizontal slit at the end of the tines
  • thinning the metal on the tines
  • cutting the tines narrower
  • cutting away an arc from the wings of the tines ("ease my flex" mod)
  • drilling holes on each tine where the slit ends -- to reduce material there ala the horizontal slit, but you said the breather hole at end of slit made them too wet, so this modification left the nib material above the ink channel in place to preserve capillary action)

After initial testing, I combined these modifications.

 

I used a dremel cut-off wheel to do the slits, a dremel grinding wheel to thin the metal, and an electric drill with 1/16" bit for the round holes (cleaned up with a file).

 

I heat set the ebonite feed in my Noodler's Ahab to an untipped Noodler's flex nib once, not for any of the individually modified nibs, under the presumption they'd be "consistent enough" in their curvature I'd not need to heat-set each.

 

Ink for initial testing is Brill "Royal Blue", the house ink brand at Gama pens in Chennai (₹25/60ml !!). The Ahab was filled with this ink, and each nib was dipped after placing on feed to prime it for writing.

 

I apologize for the inconsistent inks in the pens with combined-modification nibs, but offer the excuse that I'm trying to use these nibs more extensively to get a better feel for the different modifications and multiple colors allows opportunity to use them differently in daily use.

  • red Gama Sneaky => Sheaffer Red
  • green Noodler's Ahab => Private Reserve DC Supershow Green
  • blue Noodler's Ahab => Brill Royal Blue
  • clear Noodler's Ahab => Rohrer & Klingner Solferino

 

 

Results and Discussion

 

Here are photos of the nib modifications, with writing samples from each.

 

I was unable to make the horizontal slits of consistent size, and the size of these had a large impact on the softness and ability to spring back. Getting a more consistent slit size would improve the reproducibility of my work. I will investigate metal punches/dies.

 

I likewise was unable to thin the tines consistently. I suspect a more thorough thinning might produce a softer more pleasant flex. Since the nibs have an arched shape, I can think of no way to thin them consistently. My next experiment will leave the very edges of the tines un-thinned, as I hypothesize this will make them less sharp when using fingers to align a tightly fitting nib and feed.

 

The further back from the tip and the wider the slit, the softer the nib became and the more line variation I got. However, the furthest back and widest slit nib was sprung several times in testing. Cutting multiple slits or drilling multiple holes seems to spread the stress over more material, allowing a softer nib to still snap back - however it did not flex as far, even with thinned tines.

 

 

Conclusions

 

While these nibs do not feel like vintage flex, they provide enormous line variation and are pleasantly soft - easily flexed to several millimeters with normal handwriting pressure.

Additional testing is needed with tighter tolerances on modifications in order to determine which modifications are most beneficial.

 

I do agree that the breather hole created at the top of the nib slit makes the nib wetter. I prefer wet pens, but at least one was made too wet by this method. Additional testing with tighter tolerances will be needed to control this air/ink interchange point.

 

In actual use (ie: in a pen not recently dipped in ink), I have a lot of ink flow problems - hard starts and railroading, and drips from one pen. When the pens perform well, they are a delight to use and leave a trail of copious ink shading. Additional testing is needed in feeder modification to ameliorate the ink starvation issues.

 

I'll ask around at my local hackerspaces about metal punches and see if there's a CNC mill I could use to do the tine thinning more consistently. I've started reading up on feeder theory, but it's complex and I'm going on vacation soon so it'll be a while before I have new results.

 

 

 

 

 

 

 

Peer review and reproduction are, of course, encouraged :)

Edited by ASCIIaardvark
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Aardvark, fascinating stuff. The idea about multiple slits or holes fistributing the stress is very interesting. Regarding feeder theory, see notes above from Amadeus about a feeder where the air canal is on the opposite side of the feed from the ink channel. Great idea about using makerspace resources -- hadnt thought that there might be an advanced version of one of these with a CNC mill.

Reviews and articles on Fountain Pen Network

 

CHINA, JAPAN, AND INDIA

Hua Hong Blue Belter | Penbbs 456 | Stationery | ASA Nauka in Dartmoor and Ebonite | ASA Azaadi | ASA Bheeshma | ASA Halwa | Ranga Model 8 and 8b | Ranga Emperor

ITALY AND THE UK

FILCAO Roxi | FILCAO Atlantica | Italix Churchman's Prescriptor

USA, INK, AND EXPERIMENTS

Bexley Prometheus | Route 54 Motor Oil | Black Swan in Icelandic Minty Bathwater | Robert Oster Aqua | Diamine Emerald Green | Mr. Pen Radiant Blue | Three Oysters Giwa | Flex Nib Modifications | Rollstoppers

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This reviewer is tempted to consider this work as useful in view of the large amount of data presented.
Lack of theoretical background does not reduce the value of the data but it leads to ambiguous statements ("don't feel like vintage flex"). Also there is no guarantee that the results are objective since they rely on the ability (?) of the user to reproduce the same level of force with the various nibs tested. Moreover, the author should note that enhancement of the ease of flexing comes at the price of reduced safety limits. It is evident, for example, that nib #4 is severely sprung. Therefore, the fact that it produced for a single time the line variation depicted in the photograph is without any meaning since it already failed in the process.
I am afraid that I would recommend rejection from Science and/or Nature but given the effort (and the humor) of the author, I would suggest an alternative publication venue, such as FPN, which would be a rather appropriate one for these results.

:D :D :D Reviewers are nasty people, don't take this too personally :lticaptd: :lticaptd: :lticaptd:
Serious - thank you very much!

Edited by antoniosz
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ASCIIaardvark

I like your approach and even it is not adhering to scientific standards (antoniosz) reading it inspired an interesting idea. :rolleyes:

 

Putting a hole or horizontal slit at the end of the slit has a weakening effect onto the tines. The reason is the taking away of material. But it also has sometimes the unwanted side effects of pens writing too wet... :huh:

 

May I suggest not to drill a hole at the end of the slit but rather two holes either side near the end of the slit far away enough from the air canal (chanal) that no air leak can happen. Drilling holes is accurate (diameter and placement, use centre punch) and can result in almost the same flex characteristic. This process would be more repeatable and would offer many variations. B)

 

And if you want the tines softer, drill two holes either side! :P I would suggest diameters between 0.5 and 0.8mm. Instead of thinning the material I could imagine an ornament pattern of holes. It could be used to determine where and how much the tines should bend.

 

I wish someone would pick up this idea, it should work. I still can write and think but need someone to do the job. That would be great.

with kindness...

 

Amadeus W.
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  • 2 weeks later...

Thank you all for posting your work -- real scientists publish!

...and "mad nib scientist" sounds like a fun title :)

 

 

Introduction

 

I don't feel qualified to peer-review this thread's previously published work, so I've attempted to reproduce your results in an independent lab (my garage). I've also examined the suggestion of thinning the metal one of your peer reviewers mentioned, tho measuring the thickness of the reduction and thinning a consistent amount are beyond my available tooling and current ability.

 

 

Methods

 

I modified only untipped Noodler's flex nibs, to isolate the modifications as the only experimental variable (and because they are cheap). I tried several modifications:

  • cutting a horizontal slit at the widest point on wings
  • cutting a horizontal slit at the end of the tines
  • thinning the metal on the tines
  • cutting the tines narrower
  • cutting away an arc from the wings of the tines ("ease my flex" mod)
  • drilling holes on each tine where the slit ends -- to reduce material there ala the horizontal slit, but you said the breather hole at end of slit made them too wet, so this modification left the nib material above the ink channel in place to preserve capillary action)

After initial testing, I combined these modifications.

 

I used a dremel cut-off wheel to do the slits, a dremel grinding wheel to thin the metal, and an electric drill with 1/16" bit for the round holes (cleaned up with a file).

 

I heat set the ebonite feed in my Noodler's Ahab to an untipped Noodler's flex nib once, not for any of the individually modified nibs, under the presumption they'd be "consistent enough" in their curvature I'd not need to heat-set each.

 

Ink for initial testing is Brill "Royal Blue", the house ink brand at Gama pens in Chennai (₹25/60ml !!). The Ahab was filled with this ink, and each nib was dipped after placing on feed to prime it for writing.

 

I apologize for the inconsistent inks in the pens with combined-modification nibs, but offer the excuse that I'm trying to use these nibs more extensively to get a better feel for the different modifications and multiple colors allows opportunity to use them differently in daily use.

  • red Gama Sneaky => Sheaffer Red
  • green Noodler's Ahab => Private Reserve DC Supershow Green
  • blue Noodler's Ahab => Brill Royal Blue
  • clear Noodler's Ahab => Rohrer & Klingner Solferino

 

 

Results and Discussion

 

Here are photos of the nib modifications, with writing samples from each.

 

I was unable to make the horizontal slits of consistent size, and the size of these had a large impact on the softness and ability to spring back. Getting a more consistent slit size would improve the reproducibility of my work. I will investigate metal punches/dies.

 

I likewise was unable to thin the tines consistently. I suspect a more thorough thinning might produce a softer more pleasant flex. Since the nibs have an arched shape, I can think of no way to thin them consistently. My next experiment will leave the very edges of the tines un-thinned, as I hypothesize this will make them less sharp when using fingers to align a tightly fitting nib and feed.

 

The further back from the tip and the wider the slit, the softer the nib became and the more line variation I got. However, the furthest back and widest slit nib was sprung several times in testing. Cutting multiple slits or drilling multiple holes seems to spread the stress over more material, allowing a softer nib to still snap back - however it did not flex as far, even with thinned tines.

 

 

Conclusions

 

While these nibs do not feel like vintage flex, they provide enormous line variation and are pleasantly soft - easily flexed to several millimeters with normal handwriting pressure.

Additional testing is needed with tighter tolerances on modifications in order to determine which modifications are most beneficial.

 

I do agree that the breather hole created at the top of the nib slit makes the nib wetter. I prefer wet pens, but at least one was made too wet by this method. Additional testing with tighter tolerances will be needed to control this air/ink interchange point.

 

In actual use (ie: in a pen not recently dipped in ink), I have a lot of ink flow problems - hard starts and railroading, and drips from one pen. When the pens perform well, they are a delight to use and leave a trail of copious ink shading. Additional testing is needed in feeder modification to ameliorate the ink starvation issues.

 

I'll ask around at my local hackerspaces about metal punches and see if there's a CNC mill I could use to do the tine thinning more consistently. I've started reading up on feeder theory, but it's complex and I'm going on vacation soon so it'll be a while before I have new results.

 

 

 

 

 

 

 

Peer review and reproduction are, of course, encouraged :)

I had a look at your work...

 

Number 6 would be my favourite. ;) (the easy my flex wings should work the same, just does not look as sleek!)

 

Number 4 should work... if you knock the nib just below the slit or slightly towards the tip along the edge, the tines should close. :rolleyes:

 

great effort! B)

with kindness...

 

Amadeus W.
Ingeneer2

visit Fountain Pen Design

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