Fountain Pen Nib Tuning: How to Smooth, Adjust, and Fix Your Nib

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The first nib I ever tuned was a Lamy Safari Fine that scratched so badly it skipped on every leftward stroke. I had owned the pen for about three weeks, and I had mostly resigned myself to the idea that this was just what fountain pens felt like — a little gritty, a little inconsistent. Then I read a thread on a forum, bought a sheet of micromesh and a 10x loupe, and twenty minutes later the pen wrote like a different instrument. The same nib. Same ink. Same paper. Just two minutes of figure-eight strokes on 12000-grit polishing film.

That moment changed how I think about fountain pens. Most of the “bad pens” I had owned were not bad at all. They were untuned. The factory had done about ninety percent of the work and left the last ten percent for the user, and once I learned the basic moves I could rescue almost any pen on my desk in under half an hour.

This guide walks through the diagnoses and the fixes. It also tells you, just as importantly, when to stop touching the pen and send it to someone who has done this for twenty thousand hours. You can ruin a good nib in about three seconds with the wrong tool. The whole game is knowing what is yours to fix and what is not.

When does a nib need tuning

Tuning is what you do when a nib is healthy but not behaving. The common symptoms.

Scratchy. The nib feels gritty, catches on paper fibers, makes a faint scraping sound. Usually caused by tipping that has not been polished smooth, or by tine tips that are slightly misaligned and one is dragging on the paper.

Hard-starting. You uncap the pen and the first stroke skips before flow catches up. Usually caused by a feed issue, a slightly dry nib, or tines that are pinched too tightly together.

Railroading. The nib lays down two parallel ink lines with a dry gap in between, especially under any pressure. This is a flow problem — the feed cannot keep up with how wide the tines are spreading. Common on flex nibs and any nib that is too dry for the ink you are using.

Too dry. Lines are anemic, feel hard, skip on fast writing. Tines may be too tightly closed, or the slit between them is restricted.

Too wet. The pen gushes, lines spread, the cap fills with ink. Tines are too far apart, or the slit is too open.

Baby’s bottom. A specific factory grinding flaw where the very tip of the nib has been ground too round, leaving a tiny convex valley between the tines. The pen will hard-start on light strokes but write fine on firmer ones. Common on Western Mediums and Broads from a few major brands.

Misaligned tines. Look at the nib straight-on with magnification — the two tines should meet evenly. If one is higher than the other, you will get a scratchy, inconsistent line.

If your symptoms match one of these, tuning will probably fix it. If your nib is bent, sprung (permanently spread open from over-flexing), cracked, or has the tipping knocked off, you have a repair, not a tuning. That is a different conversation.

Tools you actually need

Most of nib tuning needs four cheap things. Skip the gadget rabbit hole.

A 10x loupe. Non-negotiable. You cannot fix what you cannot see. A jeweler’s loupe with built-in LED light costs around 15 dollars. Get one with at least 10x magnification — anything less and you cannot see tine alignment clearly.

Micromesh sheets in 1500, 3200, 6000, 8000, and 12000 grit. Polishing films, not sandpaper. The grit numbers go up as the abrasive gets finer. Around 10 to 15 dollars for a starter pack on Amazon or from nib-supply specialists. The 12000 is the one you will use most.

A brass shim, 0.001 inch thick. Brass is soft enough not to scratch the nib but firm enough to slide between tines and clear debris or adjust spacing. A small sheet runs maybe 5 dollars and lasts forever.

Ink. You need ink in the pen while testing. Use a flow-neutral ink you know well — Waterman Serenity Blue, Pelikan 4001, or Iroshizuku Take-Sumi. Save the difficult inks (very dry, very saturated) for after the nib is dialed in.

Optional but useful: a magnifying lamp if your eyes are tired, a small piece of fountain-pen-friendly paper for testing (Rhodia, Tomoe River), and a set of tweezers. Some people use a microscope at higher magnifications. I have used a phone camera in macro mode and it works fine.

What you do NOT need: any tool that says “nib smoother” on the package and costs forty dollars. Almost all of them are either micromesh in a fancy holster or a polishing pad of unknown grit. Buy the films directly.

Step 1: Diagnose with the loupe

Before you touch anything, look. Get the pen under good light, ink it up if it is not already, and write a few lines on a clean sheet. Then look at the nib.

Hold the pen so the nib points toward you. With the loupe, examine:

Are the two tines exactly even at the tip, or is one higher than the other?
Is the slit between the tines straight and consistent, or does it wobble or close up at the tip?
Is the tipping (the small ball of hard metal at the very end) smooth and rounded, or does it look pitted or have visible facets?
Is there any debris in the slit?

Then turn the pen 90 degrees and look at the tip from the side. The profile should be a smooth, rounded shape that meets the paper across a small area. If the very tip looks like it has been ground flat or slightly hollowed, you may have baby’s bottom.

Write on a fresh sheet — slow, deliberate strokes in every direction (up, down, left, right, diagonals). Note which directions feel scratchy. Most scratchy nibs are scratchy in only one or two directions. That tells you where to focus.

Almost every fix I describe below starts with a diagnosis from the loupe. Do not skip it.

Step 2: Smooth a scratchy nib with micromesh

This is the single most useful technique in nib tuning. Most “bad” nibs out of the box just need a minute of polishing.

Ink the pen. Lay a piece of 12000-grit micromesh flat on a hard surface. Hold the pen the way you normally write with it, and on the micromesh, write small figure-eights — slow, light, in every direction. Do not press hard. The pen should feel like it is gliding on slightly soft paper.

Twenty figure-eights. Wipe the nib. Test on real paper. If still scratchy, twenty more. If smoother but not perfect, switch to nothing finer than 12000 and just keep going. You should not need to drop down to coarser grits for ordinary smoothing — they remove material faster, which is exactly what you do not want.

The principle: you are polishing the tipping, not grinding it. Light pressure, varied direction, frequent testing. If the pen suddenly writes broader than it did before, you have removed too much material and you cannot get it back. Stop early and often.

For a nib that is scratchy in one specific direction (say, dragging only on left-strokes), bias your figure-eights to favor that direction. The tipping has a high spot somewhere, and you are gradually leveling it.

Step 3: Adjust tine alignment

If the loupe showed you that one tine sits higher than the other, you have a misalignment. This is one of the most common factory issues, especially on cheap and mid-range pens.

The fix is mechanical, not abrasive. Remove the nib and feed from the pen if you can do so safely (many pens this is fine, some — like Lamys — let you pull the nib straight off). If you cannot remove the nib, work with it in the section.

Hold the nib firmly. With your thumbnail or a soft tool, gently press the higher tine downward. You are not bending the whole nib — you are only nudging the very tip of the higher tine into alignment with the lower one. Tiny pressure. Look through the loupe between every adjustment.

If a tine is sitting lower, you can sometimes coax it up by flexing the nib gently against your thumb. Slow. Always check.

The mistake to avoid: do not press on the breather hole or the shoulder of the nib. You will warp the whole feed system, not just the tine. Work at the tip only.

When the tines look even under the loupe, ink the nib and test. Most alignment fixes show immediate improvement on a real paper test. If the tines look perfect but the nib still writes badly, the problem is elsewhere — flow or smoothing, not alignment.

Step 4: Fix baby’s bottom (subtle work)

Baby’s bottom is the tricky one. The fix requires removing material from the very tip without overshooting and turning a fine nib into a medium.

Diagnose first: write very slow, very light strokes. If the nib lays no ink for the first millimeter or two and then suddenly catches, that is baby’s bottom. Heavier pressure makes it write fine because the tines spread enough to bridge the convex valley.

Fix: hold the pen at a slightly steeper angle than you normally write — pen more upright. Do figure-eights on 12000 micromesh under that steeper angle, very lightly, twenty strokes. Test. The goal is to wear down the front edge of the tipping until it meets the paper at normal writing angles.

Stop early. This is the most common place to ruin a nib. If you take off too much, you cannot put it back, and your fine nib becomes a rough fine-medium. I generally recommend: if 40 figure-eights does not visibly improve baby’s bottom, send it to a professional. There is a limit to what you can fix at home with films and a steady hand.

Step 5: Increase flow with a brass shim

If the pen writes dry or hard-starts, the tines may be pinched too closely together, restricting ink flow. The brass shim fix.

Slide the 0.001-inch brass shim into the slit, starting from the tip and working back toward the breather hole. Push gently — the shim should slide in with mild resistance. Move it in and out a few times like flossing a tooth. This both clears any debris in the slit and very slightly opens the tines.

Remove the shim. Check the tines under the loupe — they should look the same, just very slightly more relaxed. Test the pen.

This usually fixes hard-starts and dryness. If the pen now writes too wet, the tines spread too much and you need to gently pinch them back together with finger pressure on either side of the nib (not the tip — work on the body of the nib).

For a more dramatic flow increase, you can use a 0.002-inch shim, but I rarely need to. The 0.001 is enough for almost every issue.

When to STOP and send to a nibmeister

Some work belongs to professionals. There is no shame in sending a pen to a nibmeister, and for the kinds of work below, sending is faster, cheaper in the long run, and dramatically less likely to ruin a nib.

Send for grinding. Custom grinds (cursive italic, architect, needlepoint, Naginata-style) require removing significant material in specific geometries. Get this wrong and you have destroyed a nib. Mike Masuyama (USA), Dan Smith of Nibgrinder (USA), Mark Bacas of nibgrinder.com, and the team at FPNibs.com (Spain) all do excellent work. Prices typically run 60 to 120 dollars per nib for a custom grind, plus return shipping.

Send for sprung nibs. A flex nib that has been over-flexed and no longer closes back up needs metalwork beyond what micromesh can do.

Send for cracks. A cracked nib needs replacement, not repair.

Send for vintage gold work. Pre-1960 gold nibs are softer and easier to ruin than modern steel. If you are tuning a vintage Waterman or Mabie Todd, send it.

Send if you have already made the problem worse. This is the hardest one to admit, but: if your first attempt at tuning made the nib write worse than it did out of the box, stop. Send it. Pay the 50 to 100 dollars to get it fixed properly rather than trying three more times and turning a 200-dollar pen into scrap.

A good nibmeister can also tell you what to learn next. Several of them will explain the work they did, which is the best way to actually get good at tuning yourself.

Permanent damage prevention

A short list of things I have done so you do not have to:

Never use sandpaper on a nib. The grit is too aggressive and will leave scratches that even 12000 micromesh cannot polish out.
Never adjust a tine you cannot see clearly. If you do not know which tine is which, you do not know what you are doing yet.
Never apply pressure to the breather hole. That is a stress point that will warp.
Never heat-set a feed unless you understand exactly what you are doing. Plastic feeds deform permanently if you go too hot.
Always test between adjustments. Your finger feel is unreliable; the test sheet is not.
Always work on a flat clean surface. A nib that rolls off the desk and lands on tile is a much harder repair than whatever made you start tuning in the first place.

FAQ

Will tuning void my pen’s warranty? Almost certainly yes, for any work that visibly modifies the nib. Some manufacturers (Lamy in particular) are pretty relaxed about it, but if you have a brand-new pen with a real flaw, send it back to the seller before you start sanding. Warranties exist for a reason.

How long does tuning take? Most fixes — smoothing, alignment, shim work — take ten to thirty minutes including diagnosis. Custom grinding by a professional takes them about an hour but turnaround time including shipping is usually a few weeks.

Can I tune a gold nib the same way as steel? Yes, but more carefully. Gold is softer than steel and removes material faster under polishing. Use lighter pressure and fewer strokes. For more on the tradeoff, see gold nib vs steel nib.

My nib was perfect and now writes worse — what happened? You almost certainly removed too much material from one spot. The fix is usually to keep polishing in opposite directions until the nib is even again, but if the nib has lost its line character entirely, send it to a nibmeister.

Do I need to clean my nib after tuning? Yes. Polishing produces tiny metal particles you do not want in your feed. Flush the section with water until it runs clear, dry it, then re-ink. See how to clean fountain pen for full cleaning steps.

What ink should I use during tuning? A medium-flow, well-behaved ink. Waterman Serenity Blue is the classic choice. Avoid very dry inks (some Pelikan blacks), very saturated inks, and any pigmented or shimmer ink during tuning — they obscure the nib’s true behavior.

Can I tune nibs I bought on eBay? Vintage or used nibs are often great candidates for tuning, but check the basics first. Look for cracks, sprung tines, missing tipping. If those are present, it is a repair, not a tuning. For more on vintage pens specifically, see vintage fountain pens guide.

How do I know what nib size I should aim for after tuning? Tuning generally should not change nib size — it should make the existing size write better. If you want a different size, that is a grind, which is a different operation. My how to choose nib size guide can help you figure out what size you actually want before you commit to a grind.

Honest downsides

You can ruin nibs doing this. I have. The worst I ever did was a Pilot Custom Heritage where I got over-eager with 1500 grit on what was actually a tine alignment issue, and turned a smooth Fine into a smooth Medium with no character. The pen still works. It is no longer the pen I bought.

Tuning is also not a substitute for buying a good pen. A poorly made nib with bad QC throughout will keep being a poor nib no matter how much you polish it. I have flushed plenty of money down cheap pens with structural problems that polishing did nothing for. Spend a little more on the pen, and tune it lightly, and you end up ahead.

Finally — tuning is a skill that takes practice. Your first pen will not come out as well as your tenth. If you have a 400-dollar pen with a flow problem, do not learn on it. Buy a 25-dollar Jinhao or a 30-dollar TWSBI Eco, deliberately make it bad, then fix it. Then practice some more. Then touch the expensive pen.

For ongoing care that prevents most tuning problems in the first place, see fountain pen care and maintenance. For ink choices that are easy on nibs, see best fountain pen inks.

Where to go from here

Get a loupe and a pack of micromesh today. Take the worst-writing pen on your desk and look at it under magnification. You will see the problem within thirty seconds — almost guaranteed. Then try one fix. Test. Try another fix.

You do not have to become an expert. You just have to be able to rescue your own pens from the small, irritating issues that 90 percent of factory nibs ship with. After a year of casual practice, your pens will write better than most other peoples’, and you will spend less money on professional work because you will only send out the jobs you cannot do yourself.

The pen is supposed to feel good. If it does not, that is information, not a verdict. Pick up the loupe.