Experiments With Flex

[Precise]

Feeds with no visible fins.

 

I've occasionally seen a pen (possibly old), with no fins visible in the feed. Perhaps there were fins or slots between the nib and the feed.

 

I've wondered about multiple ink channels. I think they might be better behaved than a single larger ink channel.

 

Storing ink in multiple channels might be an alternate to conventional fins.

 

Another possibility is channels that don't run all the way up to the top of the feed. They would be for local ink storage, rather than supply paths.

 

Alan

[Precise]

Soft rubber feeds

 

Of course ebonite is hard rubber. What about soft rubber? I have some rubber rods, to make O-Rings. They are available in diameters similar to feeds. If the rubber had a permanent upward curve, it would always press against the nib and never need to be "set".

 

It would press against the nib even when the nib flexed upwards. But that might not work well, because when we press and spread the tines, lifting the nib away from the feed, the space created increases the ink flow -- which is needed to draw a fat line.

 

A problem I've written about is the resulting fat line is awfully wet and takes minutes to dry.

 

Alan

[AAAndrew]

As has been mentioned, a flexible nib requires a lot of ink to make a line, and like dip pens, they lay down a great deal of ink.

 

If it's taking minutes to dry, it's most likely a combination of the ink and the paper. I find 25% cotton laser paper to be a good compromise of absorbent yet feather-resistant, while also having a nice surface for a sharper nib. 100% cotton can take an even wetter line, but the surface can be a bit "catchy" for sharp dip nibs. I use 100% cotton with stub dip nibs, which drop even more ink onto the paper, and it works beautifully.

 

I'd also look at the ink. Some inks take a long time to dry even in a stiff nail of a fountain pen. If you are using Pelikan 4001, a nice ink for both flexible nib fountain pens as well as dip pens, and it's taking that long to dry, your paper is probably not allowing any ink to be absorbed, but the ink just sits completely on the surface.

 

For practice or taking notes, I'm a fan of the Black 'n Red notebooks. They can take a heavy flow of ink, as long as it's not too "wet" of an ink, and the surface is smooth.

[lysander]

Have you guys seen this ? Neponset turned into a psychotic wet noodle

https://www.reddit.com/r/fountainpens/comments/b2qpzv/as_per_redditor_request_video_of_stylosuite/

 

I wonder if the only mod is the side angle cuts, similar to the conklin flex nib ?

[lysander]

The other nibs on his instagram are interesting too, seems like he's extended the slots and done an 'X' patterns of side cuts

https://www.instagram.com/stylosuite/

[BlueJ]

I wonder if the tip has been reground too; this Neponset seems to be able to write both broader and finer than the stock version, depending how much flexing pressure is applied. Note that the user still has to go quite slowly and that the heavy lines are also very wet.

[lysander]

From some quick experiments, the "cross" approach seems like it may be the way to go.

I actually went too far on this one and it is ridiculously flexible, far more than a zebra G, and feels more like a brush than a fountain pen, but is still quite snappy.

The feed can't quite keep up though but is not too bad considering the enormous amount of ink this uses.

Please excuse the horrible handwriting, I did this quickly and it was pretty hard to control.

 

With some smaller slit and cross cut this could be very good indeed, but being accurate is quite hard with a dremel and a cutoff wheel...

If anyone has affordable suggestions for a better way of making these cuts ?

Edited June 9, 2019 by lysander

[lysander]

Here is the status of my attempts... And no I didn't saw straight - will do better next time I'm using a piercing saw.

I'm using a Noodler Creaper to test it, and the nib is much flexier than the creaper's.

It's not a wet noodle but it's comparable to the better ones of my vintage flex pens in terms of flex and snappiness.

 

However it's not as good in terms of ink flow control - the vintage pens tend to put out just the right amount of ink whereas this one is too a fair bit too wet when flexing.

Not sure what's the solution to that issue.

 

[lysander]

Here are two recent nibs that Ive done.

The Jinhao is a #6 ground to a fine cursive italic ( pretty much by accident as I intended an extra fine but I ended up liking it ) with added cross cut in the relief hole and extended slit.

The Schmidt nib ( I think ) is a #5 ground to extra fine with the same cuts.

 

The #6 is flex and has near perfect flow - the feed needs occasional priming and may need work, but the nib just puts out the right amount of ink when flexing.

The #5 is semi flex, is medium wet to dry when not flexing but crazy wet when flexing and leaves visible droplets sitting on top of lines that take ages to dry ( but give extreme shading if one likes that ).

 

The reason for this discrepancy remains elusive. One conjecture is that this is due to having a larger cavity between nib and feed in the #5 due to differences in curvature, which results in ink collecting there and being released as a big drop when flexing, whereas the nib probably sits very flat on the feed in the #6 so that the ink can only travel as very thin film.

[Eusorph]

I have a question. Looking at my calligraphy nibs, I see a very simple method being used to add flex and I am just wondering if this has been tried on fountain pen nibs and to what degree of success. Many of the best calligaphy nibs simply have two slits cut above the shoulders of the nibs, near the tine. Just two simple cuts and flexy magic happen.

 

[Inky.Fingers]

There's no point in that. That steel nib doesn't have any tipping, so there's no point. It's very sharp and pointy.

 

Invest in a gold nib with tipping.

 

 

These and flex beyond any modern pen nibs. No fiddling needed.

 

I prefer dipped pen but on travels, a fountain pen.

 

Have fun with your flex.

[SpecTP]

this individual on reddit did an finite element analysis on the deformation.. you can see why a cross cut works

https://www.reddit.com/r/fountainpens/comments/43q8ki/ocstress_calculations_on_a_nib_more_info_in/?utm_source=share&utm_medium=web2x

[Eusorph]

this individual on reddit did an finite element analysis on the deformation.. you can see why a cross cut works

https://www.reddit.com/r/fountainpens/comments/43q8ki/ocstress_calculations_on_a_nib_more_info_in/?utm_source=share&utm_medium=web2x

 

What I am showing is not a cross cut.

[txomsy]

Wonderful thread! And lots of new ideas to try. Thanks a lot for it.

 

I think I already answered the last question. I got some Mallat 50 flex nibs for fountain pen which look exactly like that.

Edited May 7, 2020 by txomsy

[Eusorph]

Wonderful thread! And lots of new ideas to try. Thanks a lot for it.

 

I think I already answered the last question. I got some Mallat 50 flex nibs for fountain pen which look exactly like that.

 

You did. And I had this further questions: How well do they work? Better than the ease-my-flex mod? I ask, because the ease-my-flex was adopted by Kanwrite for their nibs (they manufacture nibs and pens for F.P.R. and Noodler's), so, if we can show this works better, I am sure we could ask them to use it for their nibs. And, since they also offer #5.5 an #6 14k gold nibs, that could turn out amazing.

[txomsy]

To be true, I don't remember. I'll try and look 'em up when I'm back home. Seem to remember I put them on some nib unit, but then I got a nice vintage flex piston filler and it took precedence.

[txomsy]

Well, tried them to refresh my memory. They do flex nicely indeed. But one has to consider that they are old nibs, smallish and somewaht thinner than usual, so the reason for their flexibility might be the cuts or not. Many vintage nibs were flexible without cuts.

 

I'd guess the only way to know is to try or to use specialized engineering equipment which I don't have.

[SpecTP]

 

What I am showing is not a cross cut.

if you look at the stress pattern of the FEA model, you can see that the main stress is at the hole and spreads from there. you'd have to model your own cut pattern (autodesk fusion 360) to see if the stress pattern is alleviated with your cut.

[Eusorph]

Well, tried them to refresh my memory. They do flex nicely indeed. But one has to consider that they are old nibs, smallish and somewaht thinner than usual, so the reason for their flexibility might be the cuts or not. Many vintage nibs were flexible without cuts.

 

I'd guess the only way to know is to try or to use specialized engineering equipment which I don't have.

 

Thank you. Considering that the cut is still used nowadays on calligraphy nibs, I think it does what it is supposed to do. I just wish some of the people here, with the tools to do it, would try the cut and repost on the results. I'd do it, but I don't have the tools.

[Eusorph]

if you look at the stress pattern of the FEA model, you can see that the main stress is at the hole and spreads from there. you'd have to model your own cut pattern (autodesk fusion 360) to see if the stress pattern is alleviated with your cut.

 

I don't have the knowledge to do it. Also, Kanwrite flex nibs don't have any vent holes, so the model doesn't apply. Also, also, I would prefer a real life test on a nib from Kanwrite, that already has a long slit, to know for sure.