Slitting the Nib
My entry point into the Sacred Circle of Nib Manufacturing
In one of my early stories, I told you about the secretive, almost hostile behaviour of the people in the nib production department. My time to enter into this sanctuary arrived when they had slitting problems. What had happened? Without mentioning, the cutting blade manufacturer had stopped producing their ten-year-old product, which had been slitting our nibs, reliably. The replacement discs did not perform. There had been a warning from the manufacturer but who would have thought it would cause such a problem. New is always synonymous with progress, thus, with being better.
The slitting machine set at the previous speed caused the new disc to bend, wobble and shatter as soon as the tip of the nib touched it. The binding compound of these new discs had some lubricating agent in it which was good for stainless steel, they were praised for lasting longer. But iridium, the material of the bead, needed the stiffness of the previous discs. (see the chapter on Fountain Pen Nib Materials)
The slitting machine operators were highly skilled; they positioned the nib and advanced the cutting disc manually. To centre each nib they visually aligned the disc with the bead viewing it through a stereomicroscope with a marking in its optics and a micrometer drive. They did not use any lubricant because they could not see otherwise.
Then they approached the iridium bead slowly, and once the disc had scratched its surface, providing a centring groove for the disc, they would apply more pressure and cut through the bead. Once in the stainless steel, they progressed more rapidly to the end stop of the slit or the hole.
I felt the solution lied in the field of being able to use a cutting lubricant. Much against the workers’ resistance, it was also time to build an automated machine. The workers were great but there were noticeable Monday morning and Friday afternoon batches. I promised not to tell anyone, it would all remain behind closed doors, as usual. But this time, I was inside.
By now, production had run out of some nib styles and the alarm bells rang full blast. Yep, the pressure was on. One of my previous side projects had been in the field of lubrication as used in the production of ball pen tips. Most secrets in ball pen tip production laid in the way lubrication is applied and what lubricant is used. From this project, I knew the right words for debating with the technical sales bloke of a reputable lubrication manufacturer.
The introduction of a numerically controlled advance system, (in-house custom-built) and the right lubrication soon solved the cutting dilemma. Exclusively the slitters were trained on these machines, not only because the aiming of the disc to the nibs still occurred visually but most of all, they maintained their status. Quietly, I became the hero of the nib department and was invited to their parties from then on.
Further to that, the lubrication during slitting reduced the forming of burs thus the time of rumbling, the mechanised de‑burring process, which occasionally damaged the nib. And like so often there is good in challenges, how else could I have entered into the nib production without this problem having occurred?
Nib Manufacturing Process
The material for the nib, either gold or stainless steel, was delivered in sheets or rolled up strips. In preparation for production, half metre long strips were cut for ease of handling.
As the second step, this strip was feathered so it would stay straight during rolling (sketch 1). It would have curved because the strip was rolled in different thicknesses, sketch 1.
The strips were passed through rollers, which left one edge of the strip (forming the tines) at almost its original thickness, while the other edge (forming the seat/heal) was reduced down to about half of its thickness for stainless steel and about one third for gold, sketch 2.
This work hardening would double or triple the hardness. The hardness of the thinner section would improve the stability of the nib, resulting in a firmer grip of the heel on the front part of the feeder and it would help the nib to set better in this section.
The gradual increase in thickness provided the nib with its characteristic, varying elasticity and allow the opening of the slit under pressure in the desired way so that the slit would remain straight.
Another reason for this reduction in cross-section is the price of gold. Rolling a gold strip in this fashion (two different thicknesses) reduces the nib’s weight by half (and half its cost) without any detriment to appearance but it actually approves the function of the nib. Stainless steel nibs could have been manufactured flat but this would have required another set of production and assembly tools, last but not least they have to fit on the same feed. Therefore, they are produced in the same way.
After rolling the so-called breather hole is punched into the strip, sketch 3. It becomes the locating hole for all subsequent processes such as stamping out the flat shape, the forming, the placement of embossments and for centring during the tipping process.
The shaping of the nib was completed by an initial drum polishing, namely rumbling or tumbling to remove the burrs caused by the stamping process. After tipping and slitting the nib, there was a second, much shorter rumbling. Tipping and slitting had raised much fewer burrs, moreover, after the slitting, the nib had become more delicate hence the aggregate were small pieces of wood and shells of almond kernels.
The tipping process entails the welding of the tiny bead of Osmiridium onto the tip of the nib. Three different size beads were used for the various widths.
The beads were welded on, using electric resistance welding under an inert gas atmosphere. Generally, when resistance welding, the materials of the components to be joined need to have a similar melting point. Furthermore, the amount of energy required to bring both parts to their melting points must be approximately equal so that they melt at the same point in time. This is determined by the physical size of the components as well as the heat capacity of the materials.
In the case of nibs, the components are as different as can be.
- the bead is tiny in comparison with the nib
- the melting point of osmiridium is around 2500 ºC
- gold’s melting point is around 1100 ºC
- stainless steel’s melting point is around 1430 ºC.
If the parameters don’t match, one component would melt before the other and vaporise, at least partially.
Dilemmas such as this are part of an ingeneer’s life; you love it or change your profession. We did it and kept our success humbly quiet.
Shaping of Tip
During my fountain pen days, all nib tips were manually shaped to a specific width and angle. After the slitters, the tip shapers were second in the pecking order. Shaping was performed before the slitting, that’s why the nibs had to be aligned visually. The burrs were removed during the final polishing. During those days I was a bit of a calligraphy buff, hence, I learned how to shape tips.
Just a comment: In the sketches I left the tip round, spherical for ease of drawing.
About the slitting, I have talked already extensively at the start of this chapter. I mention it here for the sake of completeness.
The setting was another labour-intensive, highly skilled process. It involved two actions. First, the slit needed to be closed again on the tip otherwise the ink would not move towards it. Consider: When the slit is cut with a diamond blade, the slit walls are parallel, initially. However, after a while, the slit would even widen towards the point due to uneven wear on the cutting blade. After this non-parallelity increased too much (more than 0.1mm), the end of the utility of the blade had been reached.
The tines were brought together through impacting on their outer edge, the free side of the nib leaf, photo 2. Through this impact, the material would be elongated in this section and consequentially, the slit would close at the tip. Often this embossing would happen on the underside to hide it or through embossing of ornaments and turn the impact into a feature.
At this stage of production, the ink would still stay in the slit and hardly cross over to the paper surface, unless pressure is applied to the nib and paper fibres are brought into contact with the ink. Therefore, after the nib has been slipped onto the feed of the completed fountain pen, the assembly returns to the nib department for the final nib manipulation.
In this second setting process, a tine is grabbed close to the bead with a small pair of flat pliers. Each tine is rotated inwards, courageously, until a minute plastic deformation occurred, see photo 3. The left section of inward bending I marked with a pink line which leads on as a dotted line; the right bend I kept unmarked for better visibility. This residual bend achieved an upside-down “V” shape, sketch 4.
In sketch 4, I have overemphasised the bending of the tines as well as the proportion of the opening. In reality, this shaping is very tiny; the opening falls into the range from 0.15 to 0.25mm, which depends on the width of the nib. Just remember: this was the way, we did it 30 years ago; surely, nowadays the process would be mechanised.
The final touch was given through de‑burring the edge of the gap in the bead with a knife blade shaped (oil-free!) diamond polishing stone. I marked the area in red in sketch 4. The result was the smoothest writing you have ever experienced.
Through this shaping, the lower section of the slit was always be kept apart and remained filled with ink. Through a gentle touch only, the fibres of the paper would enter into that gap and readily absorb the ink. I have described in a paragraph on pressureless writing in the article Fountain Pen Nib Mechanics. towards the end of the chapter on Nib Mechanics.
All this setting was highly skill-based, relied on trial and error and had to be tested continuously, in real life. Therefore, this happened all while ink was on the nib. What a messy business. You could not wear gloves, they would prevent the right feel, nor use barrier cream because it would change the nib’s performance, which would interfere with the setting procedure.
Setters always had blue fingers, it was an unspoken sign of their elite kudos.
In days of old, it would take about four months to break in a new nib through the wear caused by the owner’s personal writing style. I remember, when some earnest writers would come to the factory to pick up their fountain pen and ask for an experienced setter to accelerate this process.
The personalisation took only a few minutes during which the rather more than less shocked owner would be asked to write their signature about twenty times on 2000 grid wet and dry polishing paper.
And… extremely occasionally, a customer would ask about the people who made it all work. Those would have been some highlights of my working life when I had the opportunity to meet a customer. Sometimes, they asked questions, and occasionally, after they had asked for it, I would give them a company tour through the sections where their fountain pen had been manufactured.
This article on nib manufacturing is by far the most popular on this fountain pen design website. The entry page to this page is Fountain Pen Nibs. The next chapter to continue, where the knowledge of the previous chapters on nibs is applied is Design of Fountain Pen Nibs.
Above all: Enjoy!
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14 August, 2022 at 9:03 pm
Wonderful article again.
I usually wide the slits of my stainless steel nibs; they tend to run too dry for my taste, although other than that, they are perfect for me and I prefer them over others with the classical form.
At first because of the direct feeling they provide, without being a ballpoint or such a thing.
This way, I have ruined a lot of material, but also improved a lot. Immensly improved!
You know, creative playing is part of the fun, and if you are creative in one direction, you often are elsewehere too.
But freely spoken, mine’s not a professional workshop! 😉
15 August, 2022 at 12:24 pm
Thank you, Alfred
Yes, subtle widening of the slit certainly softens the writing experience. And, it requires mostly trial and error, particularly when you want to adjust different nibs. It’s different when you work for a company and do hundreds a day.
Yes, creativity spreads in all fields of one’s personality. With age, engineering has moved out of my life, while other forms of artistic, creative expression have remained and developed further. C’est la vie.
26 November, 2017 at 6:55 pm
Hello dear Sir: You are a Master! Your blog content is excellent… You are a man neccesary in Foro de Estilograficas… Your participation would be very useful!
Best regards and congratulations
In Foro I am: calamardino5
22 February, 2022 at 7:17 pm
thank you for your suggestion. How would I go about it? I would love to get involved.