Experiments With Flex

[Detman101]

14 hours ago, Grayspoole said:

 

 

 

These look very similar to the Zebra or vintage dip pen nibs that I have turned into Frankenpens on occasion with good results.

 

When you are ready to try again, I would second SpecTP’s suggestion to use a very smooth paper—Tomoe, Rhodia, Clairefontaine or, to a lesser degree, something like HP Premium 32 lb.

 

Dip pens are typically held at a shallower angle to the paper so try modifying your grip to accomplish this.

 

And finally, a little careful smoothing on Micro-Mesh, Arkansas stone, or another fine abrasive may help.  The nib is not tipped, after all.

All very good recommendations to be taken into consideration at a later date, thank you.

[dipper]

Dip pen smoothing and upstrokes:

The top sketch above shows a magnified view of the tips of the tines of a new unused dip pen. 

 

The central sketch shows how the tips tend to wear down in use. The same result might occur by smoothing the tip on a fine oilstone if the pen is held at one angle only when smoothing.

Down-strokes and side-stokes are now much smoother, but in an up-stroke the sharp chisel edge at the upper edge of the tip is liable to dig into the paper. 

 

The third sketch shows a pen that has been smoothed mainly on the paper contact surface, plus any sharp chisel edge on the upper edge has been rounded off. Up-strokes are now possible.

 

The sketches are exaggerated, for clarity.

[Detman101]

On 2/22/2021 at 10:29 PM, dipper said:

Dip pen smoothing and upstrokes:

The top sketch above shows a magnified view of the tips of the tines of a new unused dip pen. 

 

The central sketch shows how the tips tend to wear down in use. The same result might occur by smoothing the tip on a fine oilstone if the pen is held at one angle only when smoothing.

Down-strokes and side-stokes are now much smoother, but in an up-stroke the sharp chisel edge at the upper edge of the tip is liable to dig into the paper. 

 

The third sketch shows a pen that has been smoothed mainly on the paper contact surface, plus any sharp chisel edge on the upper edge has been rounded off. Up-strokes are now possible.

 

The sketches are exaggerated, for clarity.

Awesome detail! I will perform my usual smoothing and rounding on one of the Blue Dew nibs this upcoming weekend.

[dipper]

Here is an unexpected deep connection between two unrelated activities.

 

A ) Modifying a pen nib for flex.

B ) Making a traditional wooden archery bow.

 

The remarkable connection between A and B is that both activities involve making fine adjustments to a pair of irregular elastic cantillevers. Both arts aim to achieve some desired movements and spring-back of the cantilever tips, at some target of applied force, without the cantilevers permanently deforming or breaking.

 

In a pen the elastic cantilever arms are the two tines of the nib. Metal, joined at their base to the stiffer nib shank, and both pointing in the same direction, each tine is some fraction of an inch long.

In an archery bow the elastic cantilever arms are the two limbs of the bow. Made of wood, joined at their base to the stiffer handle section, pointing in opposite directions, each limb is around three feet in length.

 

I have made a few longbows in past years, and the skills learnt then do help me now when adjusting my pen nibs.

 

Naming of names:

Nibmeister == Bowyer (pronounced bow-yer)

Tuning a nib == Tillering a bow

 

Perhaps we can learn something from an expert bowyer?

 

[DiveDr]

So I have been fiddling around with Jinhao nibs to get flex.  The most successful design so far has been to grind the sides of the shank down to the silver inlays of a 2 tone #6 nib and then do the same on the tines.  I get good line variation from 0.4 to 1mm and it is a smooth writer.  On another note, Kanwrite makes #6 flex nibs in EF to broad and ultra flex fine nibs which all write great off the bat with no mods necessary.

[Detman101]

On 2/24/2021 at 9:04 PM, dipper said:

Here is an unexpected deep connection between two unrelated activities.

 

A ) Modifying a pen nib for flex.

B ) Making a traditional wooden archery bow.

 

The remarkable connection between A and B is that both activities involve making fine adjustments to a pair of irregular elastic cantillevers. Both arts aim to achieve some desired movements and spring-back of the cantilever tips, at some target of applied force, without the cantilevers permanently deforming or breaking.

 

In a pen the elastic cantilever arms are the two tines of the nib. Metal, joined at their base to the stiffer nib shank, and both pointing in the same direction, each tine is some fraction of an inch long.

In an archery bow the elastic cantilever arms are the two limbs of the bow. Made of wood, joined at their base to the stiffer handle section, pointing in opposite directions, each limb is around three feet in length.

 

I have made a few longbows in past years, and the skills learnt then do help me now when adjusting my pen nibs.

 

Naming of names:

Nibmeister == Bowyer (pronounced bow-yer)

Tuning a nib == Tillering a bow

 

Perhaps we can learn something from an expert bowyer?

 

Precisely the technique I use to get flexier tines on ultraflex nibs.
I dont' think I'll ever need a gold nib...steel is just fine.

[DiveDr]

Would not rule out gold nibs, some are worthless nails indistinguishable from a steel nib in their overall writing characteristics and the experience they provide however, there are some real jewels out there. Omas immediately comes to mind, their 18 karat gold nibs are extremely flexible, springy durable and provide an amazing writing experience, tremendous wine variation and shading in addition to being exceptionally smooth. The same can be said for Pelikan both vintage and modern nibs in this product line are fantastic. I have an M1000 with a broad nib that is exquisite, Ultra Flex and ultra-smooth and wet!

[duckbillclinton]

Unfortunately, after reading nearly all flex nib modification discussion from this forum and various websites and blogs, I would say, way too much misinformation, urban myths, and even BS are flowing around our fountain pen community...

 

Regarding flex nib modification and proper flex nib design, recently I have done extensive researches and experiments on my own, and apparently, may have found the ultimate working model... for properly modding nearly, any fountain pen to slight/ moderate (daily use) / super/ ultra flex- wet noodle (you control the option).

 

I am currently organizing and re-filtering all my findings, and plan on writing a long article to share with you-- my fountain pen pals from around the world.  The article will include proper explanation (physics/ mechanics, material science, mathematics) and step by step DIY modification process (both nib and feed).

 

Due to the very limited time I have (full time job, full time self study of Quantum Physics and Molecular Physics/ Quantum Chemistry), I am going to write my article with a new thread in this forum, and will update/ add contents from time to time, there's no guarantee if ever, this article will be finished, however, I can assure you, the info I am going to share will be more than enough for anyone to mod a flex nib pen successfully, and like I said, updates will be posted from time to time.

[duckbillclinton]

Experiment/ design 1.

[duckbillclinton]

Experiment/ design 2.

 

[duckbillclinton]

Both design 1 and 2 have similar results, wet noodle, line with variation 10x.

 

 

[Detman101]

Wow! Awesome work!!

[duckbillclinton]

wow, i m shocked.  not much response from the community, so is it worthy to write an article on flex nib mod...

[Detman101]

Flex nib modding seems to be something we all get an interest in when we first start. Then we get burned out and just shell over the cash to buy what we spent months trying to create/build.
At least...that was my experience.

[duckbillclinton]

2 hours ago, Detman101 said:

Flex nib modding seems to be something we all get an interest in when we first start. Then we get burned out and just shell over the cash to buy what we spent months trying to create/build.
At least...that was my experience.

 

Here are some of the possibilities.

 

[WalterC]

12 hours ago, duckbillclinton said:

wow, i m shocked.  not much response from the community, so is it worthy to write an article on flex nib mod...

Thank you for posting this. I, for one, really appreciate it. This is something that I experimented with a long time ago with no success. If I get ambitious I will look up this thread and try to duplicate your designs.

[duckbillclinton]

5 hours ago, Detman101 said:

Flex nib modding seems to be something we all get an interest in when we first start. Then we get burned out and just shell over the cash to buy what we spent months trying to create/build.
At least...that was my experience.

 

I need our community to respond, so an in depth discussion can take place once I start my article.

 

The reason why flex nib mod failed a lot in the past is mainly due to our overconfidence in solving the problem.  A good example would be the Ease My Flex mod, it's quite straight forward for modding the nib, but many got stuck on tuning the feed.

 

Many thinks flex nib mod is just a simple trial and error game, you slowly tune it, eventually you get it. 

 

This is NOT true.  The science behind a fully functional and fully understood flex nib design is beyond most of our imagination.  20 some years ago I obtain one of my degree in mathematics and statistics, I thought I was well prepared to understand the physics/ mechanics behind flex nib design as 100 years ago all the finest craftsman relied only on their experiences but not science theories to create the finest wet noodles, however I was completely shocked to find that a perfect designed flex nib required the knowledge of fluid dynamics, chemistry, material science, mechanical engineering, and most importantly discrete differential geometry, linear algebra, and partial differential equations.

 

Am I exaggerated? Maybe...  Amadeus W has the finest website on fountain pen designs, it's full of the most valuable information.  I owe a lot of credits to him for opening up my eyes in fountain pen physics/ mechanics and chemistry.  However, his information is not deep enough.  Most people believe drawing out a successful wide stroke relies on capillary action, gravity, and a very flexible nib, so much of the attention had been put into feed modification (to provide more ink flow) and nib (to allow tines to be easily open).  However, even with a fully dripping pen feed and a nib with 4mm tine flex range, the writing experience is still horrible, and railroads like a mother.  I am sure a lot of you had this experience, and I am in no exception.  There were occasions I almost ninja chop my fountain pen.

 

So, what factor mainly cause railroading?  Has anyone ever noticed,  as soon as the tines are open, ink flow on a wide stroke is no longer just controlled by capillary action, but also relies on the ink film (bubble) created by the paper, 2 tines, breath hole (optional), and feed?  As soon as this thin film ruptures, railroad starts.  So to successfully maintain a stable ink film (bubble), you will guarantee a continuous wide stroke, and you can continuously writing this wide line till you run out of ink or paper.

 

 

Then...  Wait a minute... Has anyone ever look into thin film equation?  It's One of the most fascinating differential equation in fluid dynamics studies.  Oh, (bleep), our heads are about to explode, too much friggin math we have Never heard of.  Well, you don't need to know it, you have been playing with this equation since you were very young, what?  YES, soap bubbles!

 

In fact, when the 2 tines open up in a nib, center slit also widens, not to mention our writing style will somehow twist the tines a bit.  What about the breath hole (moon shape, heart shape, keyhole), what about crossflex mod?  Has anyone ever think of the minimal surface problem?  Will these out of whack geometry caused by the above factors trigger a bubble rupture?  Hmm, soap bubble problem again.

 

Well, you all get it yet?  LOL.  Well, that should get your attention.  Please give me some time to organize and redo some experiments, my article will be started soon. 

Edited July 16, 2021 by duckbillclinton

[duckbillclinton]

1 hour ago, WalterC said:

Thank you for posting this. I, for one, really appreciate it. This is something that I experimented with a long time ago with no success. If I get ambitious I will look up this thread and try to duplicate your designs.

 

Nothing is too ambitious.  I can assure you,  this time you will get it right, with ease.  The question is though, will you be able to get all the proper tools (like what I am using)?  Without them, it will be difficult.

Edited July 16, 2021 by duckbillclinton

[txomsy]

I think there are many ways to skin a cat.

 

Understanding in depth the physics and the mechanics is one.

 

Trial and error is the other. And my guess is that that one is the way the original nibs came about. That and luck (good or bad) in the sense that the quality of the materials they used rendered their steel less "rigid" than modern ones (where that "rigidity" has been largely sought after for a long time). Then you just try intuitively different design approaches until you get it.

 

[Detman101]

1 hour ago, duckbillclinton said:

 

I need our community to respond, so an in depth discussion can take place once I start my article.

 

The reason why flex nib mod failed a lot in the past is mainly due to our overconfidence in solving the problem.  A good example would be the Ease My Flex mod, it's quite straight forward for modding the nib, but many got stuck on tuning the feed.

 

Many thinks flex nib mod is just a simple trial and error game, you slowly tune it, eventually you get it. 

 

This is NOT true.  The science behind a fully functional and fully understood flex nib design is beyond most of our imagination.  20 some years ago I obtain one of my degree in mathematics and statistics, I thought I was well prepared to understand the physics/ mechanics behind flex nib design as 100 years ago all the finest craftsman relied only on their experiences but not science theories to create the finest wet noodles, however I was completely shocked to find that a perfect designed flex nib required the knowledge of fluid dynamics, chemistry, material science, mechanical engineering, and most importantly discrete differential geometry, linear algebra, and partial differential equations.

 

Am I exaggerated? Maybe...  Amadeus W has the finest website on fountain pen designs, it's full of the most valuable information.  I owe a lot of credits to him for opening up my eyes in fountain pen physics/ mechanics and chemistry.  However, his information is not deep enough.  Most people believe drawing out a successful wide stroke relies on capillary action, gravity, and a very flexible nib, so much of the attention had been put into feed modification (to provide more ink flow) and nib (to allow tines to be easily open).  However, even with a fully dripping pen feed and a nib with 4mm tine flex range, the writing experience is still horrible, and railroads like a mother.  I am sure a lot of you had this experience, and I am in no exception.  There were occasions I almost ninja chop my fountain pen.

 

So, what factor mainly cause railroading?  Has anyone ever noticed,  as soon as the tines are open, ink flow on a wide stroke is no longer just controlled by capillary action, but also relies on the ink film (bubble) created by the paper, 2 tines, breath hole (optional), and feed?  As soon as this thin film ruptures, railroad starts.  So to successfully maintain a stable ink film (bubble), you will guarantee a continuous wide stroke, and you can continuously writing this wide line till you run out of ink or paper.

 

 

Then...  Wait a minute... Has anyone ever look into thin film equation?  It's One of the most fascinating differential equation in fluid dynamics studies.  Oh, (bleep), our heads are about to explode, too much friggin math I have Never heard of.  Well, you don't need to know it, you have been playing with this equation since you were very young, what?  YES, soup bubbles!

 

In fact, when the 2 tines open up in a nib, center slit also widens, not to mention our writing style will somehow twist the tines a bit, what about the breath hole (moon shape, heart shape, keyhole), what about crossflex mod?  Has anyone ever think of the minimal surface problem?  Will these out of whack geometry caused by the above factors trigger a bubble rupture?  Hmm, soup bubble problem again.

 

Well, you all get it yet?  LOL.  Well, that should get your attention.  Please give me some time to organize and redo some experiments, my article will be started soon. 

You are worlds smarter than I could ever attempt to be at this particular effort.
I have no training in fluid dynamics or mechanical engineering or anything higher-order like most that have tried their hands at this.
I'll just follow the lead of people smarter than me.
I'll be back here in the student chairs...watching and listening...lol.