Measuring Flexibility: A Proposal

[Vintagepens]

Oh, for a workable flex grading system!

 

We've had some good suggestions to date, but still no standard has been established.

I recently assembled a flex testing rig and will be putting it through its paces over the next few weeks.

 

http://2.bp.blogspot.com/-Lr2O8Ow2PNo/VZXMsMFiJwI/AAAAAAAABr8/5dhKZc0RlRY/s320/flex_test_jig.jpg

 

The basic idea is to have a method of holding a pen at a fixed angle -- 45 degrees seems a sound standard -- and of positioning weights (not shown in the photo) so that pressure on the nib can be adjusted at will.

There are many possible approaches; this one I deliberately made as simple and as crude as possible, so as to demonstrate how easily such a device could be made.

With this, one can see exactly how much a nib opens up at, say, 100, 200, and 300 grams of pressure.

Or, conversely, how much pressure is required to make it open up 0.5, 1.0, or 1.5 mm.

 

Full discussion here: http://vintagepensblog.blogspot.com/2015/07/measuring-nib-flexibility.html

 

best wishes

 

David

 

[ac12]

Agreed.

 

When I read terms like "flexi/max-semi-flex" it sound like confusing double-talk. Maybe the author understands that term, but it's confusing to me. Without the full table of terms and definitions, the terms mean little to nothing.

[mhphoto]

Bo Bo's gonna have words for yoooooouuuu…

[FredRydr]

Oh, for a workable flex grading system!

 

David,

 

Reducing flex to an empirical measure would be nice, but from my experience, finding a favorite flexible nib involves so much more than the force required to spread the tines to a certain dimension. I wish I was able to quantify it, to describe it, but I cannot. To paraphrase a US Supreme Court Justice in a case where he observed that the court "was faced with the task of trying to define what may be indefinable," he concluded "ut I know it when I see it." (The court was struggling to define "pornography.")

 

I'll be a willing guinea pig and provide you with my favorite flex nib, and then you could present me with an array of nibs that matches my nib using your measurements. Then I'll let my brain and my heart decide if the measurement is a valid one as to the flex characteristic; I'll know it when I feel it! Unfortunately, the nib is in that pen that was returned to have the cap threads issue resolved, so it'll be quite some time before I have it back, perhaps before the Columbus show.

 

Fred

Edited July 3, 2015 by FredRydr

[Cryptos]

Based on what I have read, and personal experience with dip pens, I would tend to agree with Fred. How wide a nib will spread under a given load - whichever way it is measured - says little about the writing characteristics of the nib. Some method of measuring responsiveness would be a very useful addition.

[akustyk]

David,

 

I agree completely that more and more sellers are exaggerating a nib's flexibility by pressing down on it too hard. I think that having a standardized method of measuring flex would be nice. Generally speaking, a method that would measure the amount of spread per unit of pressure is a good approach. It would give buyers a degree of confidence.

 

Your post is a reminder of how flexibility has become an obsession of so many of us. This is evident in numerous pen reviews where nibs are pressed on beyond reason just to "squeeze some line variation out of it." I am afraid we've taken this pursuit of flexiness so far that the nib's ability to flex has become one of the most desirable quality of a pen, thus giving rise to unreasonable expectations on the part of the buyer/user. As long as such expectations exist, dishonest sellers are going to exploit them.

[AAAndrew]

While David's measurements would not be the full measurement of the quality of a flexible nib, it would at least give some baseline for comparison of one element of that measurement. I welcome at least an attempt at quantifying one element of what makes a pen flexible, semi-flexible, etc...

[Cryptos]

Perhaps, but it will have to be tested on a case by case basis. There is plenty of evidence around that clearly shows that nibs with the same name and from the same maker do not necessarily conform to a standard behaviour. Essentially whatever gets described is going to be individual and not generalisable.

Edited July 3, 2015 by Cardboard_Tube

[FredRydr]

Was late 19th/early 20th century nib manufacturing an art, with methods carried only in mens' minds and never reduced to writing, waiting for discovery in pen company archives?

 

On the other hand, perhaps wonderful (but ugly) flex nibs can be found in any artist supply store, manufactured to strict tolerances that are churned out by the thousands, each identical to the other. Those might even provide a uniform standard of flex measure.

 

Fred

[Vintagepens]

Thanks, everybody, for your comments!

 

I have no illusions about the possibility of reducing the full experience of using a given flexible nib to numbers. It would be like trying to quantify a ballet performance, or the experience of consuming food. Such experiences can be expertly (if subjectively) described, but they cannot be meaningfully analyzed by being broken down to a series of objectively measurable data points.

 

All I am proposing is to measure one aspect of a flexible nib's physical characteristics, one key aspect that happens to be objectively measurable. The full expressiveness and fluidity of dancers you will have to judge by eye; but if you know that one can't jump more than a foot off the floor, it's a pretty good indication that the rest of the performance is likely to be substandard as well.

[Vintagepens]

On the other hand, perhaps wonderful (but ugly) flex nibs can be found in any artist supply store, manufactured to strict tolerances that are churned out by the thousands, each identical to the other. Those might even provide a uniform standard of flex measure.

 

Not necessarily any art store, Fred, but there are certain vintage steel dip pen nibs that were turned out in the millions and which are still in plentiful supply. The scale of manufacture was enormous, and the consistency was excellent. Certain types are particularly prized by calligraphers for their flexibility, and since they are so much a known quantity, they will offer excellent benchmarks for any quantitative grading system.

 

I have already begun to do this, in a limited way. Last week I listed a Swan on eBay, noting that it takes only 160 grams of pressure to open its nib up 1 mm, whereas a Spencerian #1 takes 220 grams.

[the_gasman]

A fascinating enterprise and a potential offering of a worthwhile objective measure, notwithstanding the caveats mentioned already.

 

There is the potential for the development of numerous indicators. Two that spring (oops -- unintended pun alert) to mind are (1) how much hysteresis is shown by the nib (i.e.the pressure registered as the tines open would be different to that measured as the tines oppose again), and (2) dynamic compliance (whereby the opening pressure might depend on the rate of application of the pressure).

 

My familiarity with science/mechanics is several decades old, so my terms (and understanding of them) might be a tad rusty. However, as an anaesthetist (hence "the_gasman") I thought that how tines open might be conceptually similar to how alveoli open.

 

Yes, you're right — I should get out more!

 

David.

[FredRydr]

Of course, we'll need an ingenious and inexpensive measuring device readily available for purchase by all who intend to sell pens. Like many measuring devices that already exist without reinventing the wheel, there may already be an instrument easily modified. I have no idea; it sure isn't up my line of work!

 

Fred

Edited July 3, 2015 by FredRydr

[Frank C]

This is an interesting proposal. I am not a big fan of flexing my nibs; I am concerned about metal fatigue. I would like to see how this works out—with someone else's nibs!

[Vintagepens]

As I noted in my blog post, while measuring how much force is required to produce a given degree of deflection is straightforward, determining the maximum safe degree of deflection is quite another matter. This is inevitably going to be a judgment call, and highly subjective.

If we were dealing with large numbers of absolutely identical nibs, one could test a small number to destruction to establish the range of flex safe for sustained usage. But since we are dealing with individual nibs, each of which is different, we are stuck relying upon "feel" and experience.

[Vintagepens]

Of course, we'll need an ingenious and inexpensive measuring device readily available for purchase by all who intend to sell pens. Like many measuring devices that already exist without reinventing the wheel, there may already be an instrument easily modified. I have no idea; it sure isn't up my line of work!

 

Fred

 

I'm not going to start manufacturing testing holders, but maybe someone else will. As my example shows, one can be thrown together very quickly out of bits of scrap wood and a cheap digital scale.

[ac12]

David,

A question, and I think you had this concern on your site.

When you are measuring downward pressure of the nib on a scale, how much of the downward pressure by the hand is absorbed by the nib flexing, such that it does not register on the scale or registers poorly on the scale? Well maybe it ultimately does register, at the point that the flex motion stops everything becomes static.

[Mauricio]

David,

 

I applaud your effort on this project. I also applaud all your efforts and contributions to the fountain pen community over the years. My comments below are not intended to be critical of you, your effort or to discredit your idea, but to offer my two cents on the subject.

 

Fairly similar devices and proposals to gauge and standardize the degree of flexibility of a nib have been discussed in this forum and other pen venues over the years. So far, all of these proposals have left more questions than answers.

 

Here are my observations about your proposal:

 

(1) It leaves too many existing variables out of the picture. This combined with several made assumptions will result in tremendous discrepancies between the readings made between two or more individuals, two or more potentially different measuring devices/techniques when making the reading, even if those readings were made to the very same flex nib.

 

(2) If you analyze the fountain pen market you will notice that nib makers, fountain pen makers, and fountain pen users across the globe have not been able to standardize the definition of nib width in firm nibs for over a century. What "medium" means to one, it might actually mean fine or broad to another pen manufacturer of fountain pen enthusiast. Change the paper, ink, ink flow in that pen and many other attributes and you can really get a lot of different line widths with the very same firm nib. Flex nibs have way more variable attributes and variables than firm nibs. It will be more difficult to keep standards true than with firm nibs.

 

(3) To me, if someone tells me his/her nib came with a factor of 100 gr, 200 gr, 300 gr, 400 gr or any other measurement in one of those scales, those statements and measurements will mean absolutely anything to me. Why? Before I look at the information provided I look at who is providing that information and what is his/her expert knowledge on the subject.

 

(4) There are many flex nibs that were not designed and manufactured to be pushed to 100 gr of pressure. Likewise, there are flex nibs that were not designed and manufactured to be pushed to line widths of 1 mm. Why push a flex nib beyond their boundaries just to come up with a weight figure?

 

(5) Several individuals doing measurements = Inconsistent methods = Inconsistent results.

 

(6) I wonder how many flexible nibs (and firm nibs, as a matter of fact) are going to be destroyed and/or damaged by individuals attempting to come up with a weight figure for their flex nibs and they do not know what they are doing. I have even seen folks making claims about their "flexible" Parker 51 and Parker 45 nibs.

 

(7) When I consider and look at a flex nib, the degree of flexibility of a nib is simply one attribute of that flex nib and not necessarily the most important one. To me, the most important criteria I see in a flex nib is the combination of the flex nib in itself, how it was setup in the pen and who did that setup. It does not matter is a nib is the most flexible one out there. What difference does it make if that nib is considered uber flex if that pen seller does not how to properly write with it? How can that seller properly set that nib up in a fountain pen body if he/she cannot even write with it (properly)?

 

(8) You need to realize that many folks venturing into flex nibs are new or fairly new to fountain pens. These are folks who do not even know how to properly hold and orientate a pen with a flexible nib on their hands. I do not think they will be able to come up with an accurate and consistent reading.

 

(9) There are many flex nibs out there that do not have fixed or linear flexibility, but different degrees of flexibility as the nib spreads its tines, some times with exponential increases. It may start not as a very flexible nib, but once they reach a certain threshold, the degree of flexibility increases exponentially. Any weight device will only give one reading at a preset line width. All those nibs with non-linear flexibility will be misread by these devices.

 

(10) Even if there was a fairly reliable system to grade the degree of flexibility of a flexible nib on a scale, how does someone train his/her fingers, hand, arm, shoulder and minds to use 100 gr or 200 gr with a certain nib? Individuals are not machines or robots that can be programmed to a certain set of weight or pressure.

 

I could go on and list additional variables and assumptions that will compromise accurate and consistent reading across the board with these proposed ideas.

 

I have always stated:

 

"The only way to properly determine the degree of flexibility of a nib is in the hands of a very experienced flex user."

 

To fountain pen sellers: If you do not know your flex nibs and are not an expert on the subject of flexible nib, please state you do not know your flex nibs and that you are no expert. True statements about your lack of knowledge on flexible nibs will actually make you more credible to a potential buyer than making all sorts of misrepresentations and embarrass yourself.

 

To buyers of fountain pens with flexible nibs: You need to be discerning. Instead of putting your emphasis on flex statements that may not hold any truth to it, buyers need to be more discerning and concerned with who is selling those pens and whether that seller has expert knowledge on the subject. In the long run, this will save you time, money and spare you of frustration and aggravation.

 

For those of you who have not seen it, I came up with a very comprehensive guide as how to how I grade my flexible nibs. Here are links to those pages:

 

"Grading Flex Nibs" ... http://www.vintagepen.net/grading-flex-nibs.html

"Performance Flex" ... http://www.vintagepen.net/performance-flex.html

[ac12]

 

Bo Bo's gonna have words for yoooooouuuu…

 

"flexi/max-semi-flex"

The problem is, BoBo understands it, but I don't.

Maybe there is some logic in how the term is built, but it is not clear to me what it is.

I've looked for a descriptive table of what his term(s) mean and I wasn't able to find one. But I also have trouble with the FPN search engine, and that is another issue.

[Vintagepens]

David,

A question, and I think you had this concern on your site.

When you are measuring downward pressure of the nib on a scale, how much of the downward pressure by the hand is absorbed by the nib flexing, such that it does not register on the scale or registers poorly on the scale? Well maybe it ultimately does register, at the point that the flex motion stops everything becomes static.

 

This would be a static measurement. If you stand on top of a coil spring set on top of a bathroom scale, the scale will register the exact same weight as if you stood directly on it, holding the spring in your hands.