Late last year I embarked on what I expect to be a year-long experiment of comparing custom nibs available from the different nib grinders currently working, focusing on those grinds from each that can be considered a specialty or “signature”. Mark Bacas is one of the most experienced nib grinders out there, and whether you’re looking for a simple tuning or a more complex grind like the “Predator Hybrid” I’m discussing today, Mark will work with you to ensure the nib is ground to your personal preferences, and that you’re happy with the result.

So What the Heck is a “Predator Hybrid” Nib?

I can only assume that the “Predator” name draws its inspiration from the shape - pictured at the top - which resembles a bird’s beak. The “Predator Hybrid” nib is ground to an ultra-fine point on the normal side, with the reverse a wider, slightly brush-like medium. To compare, a “Predator Extreme” nib has the same ultra-fine point on the normal side, with the reverse ground to a full architect. You can read Mark’s own descriptions on these and other nib grinds he offers directly on his site. I would say that on this “Hybrid” version, the reverse is slightly softer than a full architect, while still offering a bit of the line variation you would expect from that grind.

Mark Bacas Predator Hybrid Nib Writing Sample — A writing sample showing the “normal” (i.e., nib down) width, compared against the reverse (i.e., nib upside down) width.

So in practice, how do I use this nib? If you’ve read my past pen reviews, you’ll know that I value pens I can use for annotation during my reading and research. This particular nib falls squarely into that category. The ultra-fine point accommodates my tiny handwriting and allows me to make even the smallest margin notes, while the reverse side is perfect for underlining, highlighting, and even standard writing. Frankly, I’ve never had a reversible nib write well to the point where I could use the reverse side for much more than a line or two. This one is smooth enough for standard writing.

TWSBI Diamond 580 Interchangeable Nibs — The TWSBI Diamond 580 Fountain Pen is one of many that features interchangeable nib units, so you can have multiple custom nibs ground to switch among your various TWSBI Pens.

Why I Love Interchangeable Nib Units for Custom Nib Work

For this grind, I chose to have Mark modify a TWSBI 580 medium nib unit, so that I can swap the nib between my various TWSBI Diamond 580 pens. Lately, wherever possible I’ve been having nib grinders modify interchangeable nib units from JoWo, Bock, and TWSBI so that their work isn’t tied to any particular pen. It’s quite helpful to be able to move the nibs around at times - some grinds are more suitable to different pens, depending on weight, balance, etc., and these threaded nib housings make swapping nibs a cinch.

Cost of Nib Modification - Cheaper Than Buying a New Pen

The grind featured here cost $50, and since I did not pay a rush fee, it took several weeks for Mark to turn around. (Mark is fast - some nib grinders take months, or even up to a year.) In response to posts like these, I often get the question: “Why pay extra money to ‘fix’ a pen that should write perfectly out of the box?” Here I think we need to break down the question a bit: Are you paying to fix a manufacturer’s flaw with the nib, in which case I absolutely agree with you that the cost of any repair should be born by the company that made the pen, or are you looking to personalize the pen for how you write? It should be fairly obvious that if you write extremely small, a standard stainless steel extra-fine nib may not be narrow enough for you, and you should consider a needlepoint or a nib like the Predator.

Mark Bacas Predator Hybrid Comparison — The “normal” point of the Predator nibs writes a ***very*** fine line, even finer than a needlepoint nib like the one ground by Kirk Speer (Pen Realm) for Esterbrook.

Even with standard nib widths, it’s impossible for a manufacturer to anticipate things like the amount of pressure you use and how you hold the pen. I have pens in my collection that, out of the box, wrote within “the range of reasonableness” and wouldn’t be considered defective, but still didn’t work for me until I had them tuned. I would estimate that 80-85% of the pens in my collection have been modified or tuned from “factory standard,” either by a nib grinder or yours truly. At the end of the day, if you love the look of a pen, and it’s not writing perfectly, consider paying a little extra to make it yours. If you keep it for years, you’ll get more enjoyment from the writing experience than the $20-50 modification fee, and in many cases it’s cheaper than buying a new pen.

Getting Started: Create Your Workspace

Necessary precautions are minimal. Basically, you need a well-lit workspace with a towel or other no-roll surface to hold your pens and nibs. The number-one danger when performing any sort of work or maintenance on fountain pens is dropping a pen onto the floor and cracking the pen barrel and/or bending the nib, so make sure your pens are secure. I typically unroll a towel onto a sink or standing desk and use that as my work surface.

Swapping out interchangeable nib units (discussed further below) doesn’t require any special tools. Otherwise, you will likely need a square of rubber to help grip the nib and feed, and possibly a loupe or other magnifier to align nib tines.

Franklin-Christoph fountain pens use JoWo nibs, so it’s easy to amass a large collection of custom-ground F-C nib units that you can swap between all of your JoWo-compatible pens.

Easy: JoWo, Bock, and TWSBI Interchangeable Nib Units

These days, the majority of pen makers no longer manufacture their own nibs in-house, and instead purchase nibs from third-party companies JoWo, Bock, and to a lesser degree, Schmidt (though I find Schmidt nibs excellent and don’t know why they’re not more widely used). While some people complain about monotony and the lack of expressiveness in how these modern nibs write, there is one key advantage to this uniformity: interchangeability. Many, if not most, pens that accept standard JoWo or Bock nibs use a default nib unit (i.e., a nib and feed seated in a threaded housing) that can easily be unscrewed and used in another compatible pen. Once you start custom-grinding these nib units or gather the range of nib sizes, it becomes a very versatile platform that can allow you to thoroughly enjoy your pen collection.

The process for swapping out a JoWo or Bock compatible nib unit is mostly the same between brands. Gently grasp the nib and feed and turn counter-clockwise to unscrew the unit.

The process itself is simple. First, if the pen you are working on is a cartridge-converter model, remove the converter. Then, gently grasp the nib and feed and turn the nib unit counter-clockwise to remove it. Select your new nib unit, insert it into the section, and rotate clockwise until secure. Do not overtighten, as this can misalign the tines of the nib, at best, and cause stress damage to the nib housing, at worst, in which case you will need a replacement.

Opus 88 pens, which are Japanese-style eyedroppers, add one slight wrinkle to the process. There is a small o-ring attached to the bottom of the nib unit housing. If replacing with a non-Opus nib unit, don’t forget to transfer the o-ring as well. It sits on the plastic “stem” and is easily removable.

TWSBI nib units are slightly different, though still simple. On the TWSBI Diamond 580, you simply unscrew the front section of the pen and slide the nib unit out of the plastic cover (shown here in red but clear on most current 580 models). Insert your new nib unit and reassemble. Because TWSBI sells spare nib units for the express purpose of allowing you to easily switch nibs between pens, you don’t have to worry about voiding your manufacturer’s warranty or otherwise causing unintended damage. I own several spare TWSBI nibs, some of which have been custom ground to specialty nibs such as architects.

Editor’s Note: There has been a lot of press recently about a manufacturing defect that has caused cracks in JoWo nib housings. While I’ve been lucky and have not yet found the issue in any of my personal pens, JoWo has released a series of announcements discussing how they plan to fix the problem. If you have been inspecting your JoWo nib units and discover cracks, please reach out to Meister Nibs, the U.S. JoWo distributor.

Intermediate: Pulling and Setting Friction-Fit Nibs

But what about pens that don’t use interchangeable nib units? Well, the nibs on those pens are, for the most part, equally “swappable” and the process is no more mechanically complex than taking a small square of rubber or other grippy material, grasping the nib and feed, and pulling both out of the front end of the pen’s section using a steady motion. You replace a nib the same way, though you need to be pay attention when reinserting the nib and feed as some pens have grooves or “guides” that determine exactly how the nib is supposed to fit.

The nibs on some pens, especially those with proprietary in-house nibs like this Platinum 3776, do not come in a housing, meaning that the nib and feed sit directly inside the custom section.

So why do I have this categorized as requiring an “intermediate” skill level? Honestly, it’s more about confidence than skill. Sometimes, things don’t go 100% as expected. Old ink residue may cause the nib and feed to get stuck in the section, and you may find yourself having to pull fairly hard or jiggle the nib a bit (gently!) to dislodge it from the pen. Any time you apply force, you run some risk of misaligning the nib tines or cracking the feed. Changing friction-fit nibs properly requires some patience, a willingness to engage in a bit of trial-and-error, and an “intermediate” understanding of how fountain pens work. Finally, keep in mind that if your pen breaks and you can’t fix it on your own, the manufacturer might consider removing or swapping the nib on a pen without an interchangeable nib unit to be a “modification” that voids your warranty. That’s not to say that you won’t be able to find someone who can fix the pen, but you will likely have to pay for it.

From the top: Platinum 3776 UEF in Schon Black Ultem, via Flexible Nib Factory JoWo housing; Pilot PO Nib in Newton Shinobi, via same housing; Platinum 3776 in an Opus 88 Jazz, via same housing.

Expert: Custom Nib Housings for Maximum Pen Hacking

The last topic I plan to discuss combines the two techniques discussed above in a manner that allows you to create your own custom nib units. Flexible Nib Factory sells custom nib housings designed to pair proprietary nibs and feeds (i.e. Platinum, Pilot, Pelikan, Sailor, etc.) with JoWo and Bock-compatible pens. For example, I pulled a friction-fit medium 14k Platinum nib from a standard Platinum 3776 fountain pen, and inserted both the nib and feed into a JoWo-compatible Flexible Nib Factory housing, which I then seated in an Opus 88 Jazz. The one drawback is that these custom housings won’t accept a converter, so you will need to use a piston filler, eyedropper, or bulkfiller-style (i.e. Conid) pen. Opus 88 pens work great for these types of modifications, though with certain brands like Platinum you may have to trim the plastic end on the back of the feed in order to allow the Japanese-style eyedropper system to close.

A nib unit disassembled. Using Flexible Nib Factory housings, you can pull, for example, a nib and feed from a Platinum 3776 and insert it into the custom housing designed to fit a JoWo or Bock pen. It’s less complex than it looks.

A word of caution: customizing fountain pens in this way is addictive. Since building my FrankenJazz, I’ve also moved another Platinum 14k UEF (Ultra Extra-Fine) nib and a Pilot PO (Posting) nib into JoWo housings, which are now in a Schon Black Ultem and Shawn Newton Shinobi. I’m eyeing several other nibs in my collection that don’t get much use in their current setup…

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