Kaigelu 316 Plunger Filler: Forming the Blind Cap

The Kaigelu's heavy end finial is a hefty lump of solid brass. This is a press fit on the acrylic barrel, and glued into place for good measure. Once I managed to winch the swine out, it was the natural candidate to act as the plunger rod's blind cap.

Arrowed: The open blind cap, revealing the Kaigelu's plunger rod.

Ambivalent about how to proceed with the blind cap, I found myself avoiding the whole subject till everything else was finished!

A closer look.

Typically, any self filling pen has the blind cap mounted on a threaded boss so that it may be unscrewed. The simple Woods valve arrangement as used in the 616 vacumatic conversion would have sorted this out in the space of a few minutes, but I was very reluctant to take that path - it would have meant adding yet more weight high up an already top-heavy pen. 

Instead, the Kaigelu's blind cap gets a (negligibly) lighter snap ring. The snap ring also allows for more tinkering in the future, I would like to eventually see a ink shut off valve control crammed in there along side it.

Now, I like the idea of a ink shut off valve. I feel less unequivocal towards the design favoured by every plunger filler manufacturer, in which the same threads work both the blind cap and the shut off valve. My gravamen here is the consequentially counter-intuitive habits required of the user (blithely says the guy making an unheard of snap ringed blind cap). Fill the pen, screw down the blind cap, then back off "a few" turns? Get used to writing with the blind cap ajar? I could live with it, but it's not my cup of Oolong.

As an alternative, I'd much rather the two functions were separated: the blind cap pulled straight up and down using the snap ring, and rotated to full left or right lock to extend and retract the shut off valve, using a ballpoint style twist mechanism. All that is very much just daydreams & doodles at the moment, so let's keep focus on the Kaigelu's crude snap ring arrangement as is.

The blind cap parts, before reshaping & fitting.

To begin with, another motor pulley is used to connect the plunger rod to the blind cap, followed by this lot:

 Part 1 - an external circlip, which sits in groove cut above the pulley, preventing it from sliding off the end of the rod.

 Part 2 - a snap ring, which sits below the pulley and protrudes from the snap ring ports cut into the blind cap.

 Part 3 - a plastic washer, which gives a flat surface for

 Part 4, an internal circlip, which sits in a specially cut blind cap groove. This holds all the preceding parts inside the blind cap.

 The finial's spigot has a recessed ring keyed into it from the factory, so I used that as a guide groove for the craft saw, cutting through the metal to create ports for the snap ring to project from. The dremel-style mini drill opened up these thin ports enough for the snap ring to fit through them.

"Even Rocky had a montage!" The blind cap's snap ring extends from these ports.

The snap ring itself is just a gold plated jump ring, reshaped to a tall "C" profile with pliers.

About to test the jump ring. It needed to be bent
quite a bit more than pictured above.

Now, there are such things as internal circlips of less than 8mm diameter. In Australia. In China. But not in the UK! I had to grind down an 8mm circlip to suit. What a palaver! It actually wears down quite quickly using the roughest mini drill attachment.

Above: An 8mm spring steel internal circlip, a circlip ground
down to size, and (arrowed) its groove cut into the blind cap.

Does it fit? It fits!

As you can see in the photo below, I didn't trust myself not to scratch up the plunger rod whilst making up the blind cap! Instead, I used an off-cut from the brass rod as a guinea pig, then transplanted the components over after testing. As it happens, all the wee circlips, washers and rubber O rings came in inexpensive packs of 5 or more too, which really took the stress off. With so many spare parts, messing any up was no big deal.

The blind cap, ready to do its job. You can just make out its retaining circlip
in the main picture, while the blow-up shows the snap ring that holds
the blind cap to the barrel.

Attaching the blind cap completes the plunger filler assembly, so it's high time I uploaded a short leak test clip! Here's the happy result.

Next up: Further Mindthots. 
The final post documenting this mod wraps things up with a overview of the Vac316 build, what I would do differently in hindsight, thoughts on possible future revisions, other considerations, &c.

Kaigelu 316 Plunger Filler: Vacuum Release Chamber

Lacking just the right tool to create a bell shaped vacuum release chamber at the bottom of the barrel, I freely admit coming within a hair's breadth of ruination. The end result does work, but less gracefully than I had hoped for - there is a pronounced step between the vacuum cylinder and release chamber that can be felt as a jolt at the bottom of the plunger rod's travel.


Non, Je Ne Regrette Rien

Vraiment, I couldn't give a twirl of Hephaestus' tongs! I was taking the plunge (groan) as much for an exploration of this creative filling system as for the end result. The synopsis of this chapter in the traveller's tale is this: using a small cylindrical grinding head, followed by an small egg shaped grinding head, does not combine to make a medium sized, bell shaped release chamber. It gives a ledge, followed by a smooth bell shaped transition from barrel to release chamber.

Hollowing out a pressure release chamber near the bottom of the barrel.

Hollowing Out the Vacuum Release Cavity

The photo above shows what I was aiming for; the red highlighted area to be left untouched as the vacuum  cylinder, and the wider green area as the vacuum release chamber. The latter had to be cut above the barrel threads, so I popped some spacers onto the drill's mandrel. This really helped keep things under control - all I had to do was hold the drill and barrel together as I walked it round the circumference, to keep the thing cutting at a set depth. The polishing head shown above was of course useless, it took the rough steel heads to get things going.

I'm not even going to mention the ugly attempts to smooth out the ridge, or the haphazard north-south channel I ground as a muddle-minded aid to air and ink exchange when the barrel is near empty, so let's wash out the swarf in preparation for tomorrow's big finale.



"Flounder's Mindthots",  À Suivre...
Everything south of the blind cap is complete: the barrel with its vacuum release chamber, the control rod with its Goossens spindle & sliding seal, and the packing seal up top to keep all that watertight. All that remains is Forming the Blindcap, in which the Kaigelu's barrel finial (the plug on the end) is hooked up to the control rod, and outfitted with a snap ring. See you Monday :-)

Kaigelu 316 Plunger Filler: Packing Unit

About to install a rigid spacer in the barrel.

"Packing Unit" is a term that seems to have endured since the old greased felt piston packing sleeves employed in vintage vacuum fillers, so I'll stick with it for today's post regardless of the absence of any genuine "packing" in this project. This mod apes the typical arrangement used in vintage Sheaffer vac plunger "packing unit" restoration kits, with a modern rubber gasket (for my purposes, a refashioned Sheaffer PFM point seal) sandwiched between two rigid spacers in lieu of the felt packing. 

The one notable exception here is that this packing unit is secured in place between the jaws of two stainless steel circlips. Grooves cut into the Kaigelu's barrel wall accommodate a pair of 8mm internal circlips, which do the job of holding the rubber and plastic packing sandwich firmly in place near the barrel's mouth. I wonder if there's any of that funny
Bavarian ham left in the fridge.

Vacuous Ruminations
 
Where was I? Ah yes - the PFM point seal I took a chance on in yesterday's post came in a pack of two, so an unexpected choice had to be made; how many to use in making up the packing unit?

• A single seal design would leave more barrel space for the vacuum cylinder, and hopefully allow an optimal ink capacity.

• A dual seal design would take up more real estate - 12 mm of the barrel's length - and sacrifice capacity, but lend the system some redundancy in case the first seal failed.

The abortive dual seal packing unit.

I slept on it and made up my mind in the morning. Thinking was for the gloopy ones! Better to go for glory (and risk inky fingered disaster) with a single seal packing unit. With no experience of vac-plungers, it was more important to me to give the thing as large a vacuum cylinder as possible, to build up a decent displacement on the downstroke. For all I knew at the time, the length of the packing unit could have meant the difference between a pen too feeble to fill and a workable one.

I settled on fitting the thicker of the two PFM point seals (I was surprised by the lack of uniformity here!) and resolved to fly ever closer to the sun, sneering down on all Creation, with no fear of the looming  comeuppance for my temerity...


Mounting the Packing Unit

The great advantage of the Kaigelu as a modding testbed is the thickness of the barrel. Instead of adhesives, I could rely on the strength of the barrel to grind a pair of grooves, clip stainless internal circlips in them, and mount the rigid washers and rubber seal between them.

About to grind the Kaigelu's lower circlip groove.

There's lots going on in the picture above! Obviously, the higher up the barrel the packing unit was mounted, the better in terms of vacuum generated. The finial's spigot, in the background, already encroached some way into the barrel, so the top of the upper circlip had to leave this some clearance. I measured the length of the spigot, added the length of the packing unit stack (two circlips, two rigid washers, and the static seal itself), then figured out the difference between all that arithmigraine and the total length of the barrel.

Using this figure to cut a length of brass tube, and temporarily installing this tube in the barrel, gave me a useful bottom stop for the grinding head shown in the photo above.  I could be quite clumsy (as was very much the case) cutting the lower circlip groove, with minimal marring of the barrel walls.

The lower circlip groove, arrowed, and with the lower circlip installed.

I cut this first groove far too deeply, though not disastrously so, and learnt to be more cautious with the upper circlip groove -  I didn't even turn the drill on for this. A few careful circumnavigations by hand created a decent guide channel, which was followed up with less careful deepening. Cutting the groove without powered assistance gave a far better result, the top circlip clicking into place with a satisfying tension. It was pretty easy to cut the groove in precisely the right place too, simply by using the packing stack as a physical stop for the grinding head.

The upper circlip groove, cut with the packing unit in place for precision, and with the upper circlip installed.

A few brief word on the circlips before the next post continues this build...

The circlips used to mount the packing seal are 8mm stainless steel, so should resist inkular rustolescence. The circlip pliers used were cheap garbage, and I got what I paid for; the tips and arms needed a great deal of grinding down to size, and the central rivet wanted a good bash with a hammer to reduce lateral slop.

Buy cheaply, curse to excess!

Tomorrow's Mindthots...
Prepare to grit your teeth in horror. The weekend subjects the Kaigelu's beautiful acrylic barrel to some savage grinding, as the Expansion Chamber is hollowed out to release vacuum near the bottom of the plunger rod's travel. This plunger filler is almost ready to be put through its paces! 

Kaigelu 316 Plunger Filler: Shaping the Seals

The sliding seal shortly after testing for fit. There was an encouragingly loud pressure change as the O ring shifted position on the Goossens spindle during testing.

It was too much to hope for a serendipitous discovery of seals that would exactly fit the Kaigelu's barrel "off the shelf". After all, that the stars had aligned in such a way as to reveal everything else - a conveniently shaped motor pulley for the Goossens spindle, a ready supply of 2 mm diameter rods, and of course, the cylindrically barrelled and pre-blindcapped Kaigelu itself - was already bordering on the unlikely.

Anything more would have required a darker covenant; sadly, a scan through Iamblichus' On The Mysteries of the Egyptians, Chaldeans and Assyrians for the necessary invocations proved fruitless, and ultimately my efforts in this endeavour were stymied owing to a general lack of practical direction.

Nothing ventured, no Thing invoked.

Instead, the path was made clear to me by David Nishimura's mention of restorers grinding fresh cut seals to size while replacing perished gaskets. This was advice that worked out very well for both the stationary "packing" top seal - a Sheaffer Pen For Men point seal - and the sliding seal at the end of the plunger rod, a generic nitrile rubber O ring.

I've never had to grind rubber before, and the whole experience was a happy surprise. I had expected the rubber to stink as it was abraded, the sealing surface to become ragged, and for the work to make a mess, and I was wrong on all counts. You can grind down perfectly workable seals with no such hassles in a couple of minutes.

The thicker of the two PFM point gaskets, about to be ground down to fit the Kaigelu's barrel.

The great expedient of using the PFM gasket as a stationary seal was the perfectly smooth and circular precut centre hole. Similarly, by using a Goossens type spindle, there was no need to cut any kind of centre hole for the sliding seal at the end of the plunger rod. All that was required of me was to set these seals in a mandrel, and spin them against an abrasive. The PFM seal was subjected to two grades of sandpaper and some wet 12000 grit micromesh for this purpose, and took less than a minute to complete, snugly fitting the barrel cavity.

It only took about a minute to grind the PFM gasket down to fit the barrel.

The sliding seals were more oversize, so took more grinding. These are generic 5mm ID, 2mm C/S (cross section) nitrile O rings and come in a pack of 10. The convoluted arrangement below allowed me to work on two simultaneously - this meant I could get both down to roughly the right size at the same time, then take a crafty chance on grinding down one by a fraction more than the other, and compare the two for fit.

About to secure a pair of O rings
to the mandrel of a mini drill.

Like this, do you see?

As a rough guide to getting the O ring down to size, I found that if it fitted the mouth of barrel with a little resistance, then it was pretty close to perfect.

The O rings, ready to spin against the coarse and fine sandpaper (in background).

I learnt a lot from this exercise! It should be handy experience if I get an old Vac-Fill. Rubber seals take very little time, make minimal mess, and no smell to grind down to size. With a wipe of silicon on both to aid assembly, the seals passed a water test. It was interesting to hear the pressure change as the O ring shifted on the Goossens spindle. Great stuff!

Why PFM point seals anyway?

I simply couldn't find any generic rubber seals with the profile needed! Generally speaking there's not much call for a gasket with a very small diameter (< 2mm) hole, and a large outer diameter (let's say about 8mm). I did briefly consider making up an ugly arrangement using a vac-fill packing seal mounted in a rigid cylinder, which would itself be sealed in the barrel, as a fall-back position. The PFM point seals came as a happy deus ex machina escape from all of that.

Now, I'd never actually used Sheaffer's Pen For Men, but my similarly designed Snorkel did offer a clue that this model's point seal gasket was a contender for what I needed. Both pens use a filling tube that extends and retracts through a 'point seal'. Taking a ruler to my Snorkel's tube showed it was comfortably less than 2mm in diameter, guaranteeing a tight fit for the 2mm brass rod I'd chosen for this project. Unlike the svelte Snorkel, I knew the PFM had a reputation for girth, so figured its point seal would have a suitably huge outer diameter. It does.



Next time on Flounder's Mindthots...
So far, we've a plunger rod for our sliding seal, but the freshly tailored stationary seal is still looking for a home. It's time for it to move in with a pair of rigid spacers in a 'Packing Unit' at the end of the barrel! This disparate pile of plastic, rubber and brass parts is about to resemble a functioning plunger filler, so be sure to drop in when your zodiacal occultations and syzygies are most favourable.

Kaigelu 316 Plunger Filler: Control Rod

I couldn't wait to start putting the plunger rod together; as it happens, I had gleefully pounced on a small supply of the component vital to this mod's success back in December, while I was still putting together the 3rd vacumatic Hero 616: the pascal-variegating Goossens spindle.

To the fountain pen modder looking to party like it's 1905, a Goossens spindle is indispensable.

The ingenuity of the Goossens spindle came to me in a flash one evening. Half a minute - now I think of it, it must have been in HTML. On first reading this post on FPN, I was struck by the resourcefulness of the thing; a simple design that employs a generic o-ring, yet manages to maintain a pressure seal on the downstroke, and prevent back pressure on the upstroke. In addition, the ramping effect of the rigid cone should keep the system working even as the seal wears. The crude interpretation of the Goossens spindle as made for this mod is described below.


How it works:

• The top face of the spindle is a shallow cone. On the downstroke, this face drives the seal down the barrel, the taper ensuring a good seal as it does so. The o-ring creates an excellent pressure seal as it travels, even against the rough and unfinished interior of the Kaigelu.

• The bottom face of the spindle is also a shallow cone, but ported to allow ink and air to flow through it on the upstroke. 

• That's all! "Simplicity is Beauty" etc. An elegant and pragmatic idea! Richardspens.com has a potted history of different approaches to the plunger filler back pressure issue, for a brief indulgence in technical nerdiness accompanied by neat photographs of vintage pens.

How it's made:

Within a few minutes of minor sawing and grinding, a commonplace plastic mini motor pulley can be reshaped to requirements, then secured to the plunger rod using stainless steel external circlips above and below. At less than £2 for a pack of 5, these pulleys come ready made with a 2mm centre hole to match the plunger rod, and an outer diameter that fits within the Kaigelu's barrel - they're ideal!

An electric motor pulley
to fit 2mm shaft. 1.90 GBP for an eBay 5 pack.

Discarding the cylindrical section of the pulley.
This piece came in handy later on while grinding
the sliding seal, as a spacer tool.

The craft saw made light work discarding the superfluous cylindrical section, while a few seconds of holding the mini drill's grinding attachment against opposite sides of the upstroke cone face hollowed out the flow ports.

I spy with my little loupe... upstroke flow ports (arrowed).

Oddly, I found that the preformed centre hole was a little too tight for the 2mm rod, so I bored it out slighty by hand using one of those mini drill things that come in inkjet refill kits.

With the Goossens spindle ready, I used it as a guide to cut shallow grooves in the brass rod for a pair of securing circlips - a few strokes with the craft saw were all that were required here - then washed off the swarf.

A groove in the plunger rod, ready for its stainless steel external circlip.

For the final assembly, I smeared on a little aquarium sealant (there was plenty left over from the 616 vacumatic mods) in the spindle mounting area. The idea was for it to act as a lubricant while pushing the spindle into place, and also to seal any possible weep at this join after curing. I smeared a little over the circlips for good measure too.

The Goossens spindle secured to the brass plunger rod,
using stainless steel external circlips above and below.

Passive Cooling Considerations:

In some single walled pens where the barrel acts as the ink reservoir, heat from the user's hand can expand the air inside the pen. This self-repellence of the caloric encourages the captive aethers to return to the greater firmament, elbowing blobs of ink out of the nib as they rush pell-mell to liberty.

To keep the chaotic forces of nature bridled to Man's bidding, I endeavoured to temper the rate of internal temperature change through the use of a length of solid brass for the control rod, connected directly to the barrel's brass end finial using heatsink paste.

The brass plunger rod & blindcap.

Did that sound convincing? I went for brass because it's a nice colour match with the Kaigelu's gold clip and trim rings, and heavy enough to help counter the weight of the barrel's end piece. Inexpensive 2mm diameter rods are also available on eBay in stainless steel and even clear perspex, if corrosion turns out to be an issue (we'll see - my usual ink is by Diamine so probably pH neutral, and most water pipe fittings are made of brass after all).



On the next episode of Flounder's Mindthots...
Shaping the Seals, in which a pair of off-the-shelf rubber seals are tailored to fit the Kaigelu's barrel.

Kaigelu 316 Plunger Filler: Prepping for Surgery

Although a large pen in the hand, the Kaigelu 316 did require a little trimming of the sails to make best use of the space available. In particular, the grip section on these pens takes up a lot of real estate within the barrel, as does the barrel's end finial.

Making space.

In the photo above, the red area shows how modding potential is restricted before lopping off bits of the section and finial, and the green area shows the increase after. In particular, I had my eye on space taken up by the section for the vacuum release chamber.

About to cut the excess metal from the section, using a spacer
from this empty dental floss reel to protect the threads from damage.

 

Cutting the section and finial
Using the craft saw last put to use during the last two vacumatic Hero 616 mods, and a spacer to guard against clumsiness, soon made light work of the section's excess brass. At least, I think it's brass, going by the colour of the swarf in the photo below. It wasn't picked up by a magnet either.

Arrowed, left: the area of the section for the chop. Right - Sawing it off!

Smoothing out the lip.

I did this cutting with the section empty of the nib and feed, which are set in an all too easily removable sleeve. This was the one time this pen's Achilles heel actually proved helpful.

A brief pass with the mini drill smoothed out the lip, and after a good wash, the section was ready for use... or so I thought! That weak sleeve was to make a nuisance of itself one last time; more on that below.





The barrel's end finial got a trim in much the same way as the section, using a spacer before using the razor saw.

The brass finial gets the same treatment.

Securing the Section Sleeve
Ah, that troublesome section sleeve. By retrofitting this pen with a vacuum plunger filler, I had hoped the thing would cease to be an issue, as there'd be no cartridge or converter to exert mechanical force upon it during insertion. This conceit was soon exposed with the first test of the completed vacuum assembly! In fact, the pressure force of the filler's down stroke was enough to blow the sleeve, nib and feed out of the section like some sort of scribal curare dart.

The dismantled section, showing the nib, feed, sleeve and the problematic original converter.

As this post caters primarily to the Kaigelu's yawn-worthy specific idiosyncrasies rather than the actual vacuum plunger conversion, I may as well round things off with the solution to the pesky section sleeve issue. The answer lies in cannibalising a decent quality cartridge.

Top: an empty Diamine cartridge about to save the day, pictured with a couple of villains.

I was quite thrown by the pressure blow out issue, but soon realised that the sleeve would resist being pushed out the bottom of the section, if it were secured to something above the section - something too large to push through it. The screw in converter that came with the pen (no.3 in the photo above) was soon ruled out due to the awful radial cracks at its mouth (circled). A cheapo generic cartridge (no.2 in the photo) was a sloppy fit in the section. Only a decent Diamine cartridge actually clicked solidly into the section, even without the sleeve present. Perfect!

Cannibalising the Diamine Cart.

With the cart cut flush with the section, I roughened the exterior of both the cart and the sleeve to lend a key to a coat of shellac. Even the bottom of the sleeve's cartridge nipple got a thin smear before snapping them together, adopting the thread technique first used way back during my first Sheaffer Targa repair.

Foreground: The section sleeve & cart, next to the section. Background: plenty of shellac.

Before bringing all the parts together, I gave the nib and feed a wash in soapy water. Have a look at this photo of the feed and sleeve, taken prior to cleaning and installing. I presume the cut-out area of the sleeve is meant to line up with the lengthwise channels in the feed, so kept everything aligned this way when reinstalling the nib and feed into the sleeve.

The sleeve and feed, prior to washing. After only a brief period, the exposed feed has picked up quite a bit of lint here!

Strangely, I can't find any photos of the shellacked cart-sleeve-section, even though I took several at the time. The sleeve (fitted with the nib and feed) was shellacked generously, then inserted into the section. Then the entire outer surface of the Diamine cart was shellacked and snapped into place. To seal off the metal section from any ink exposure, the mouth got several shellac coats over several days. I've cropped out the picture below from the only photo I can find that shows this!

The section, after all fettling was completed.

On Flounder's Mindthots next time...
Phew! With all that donkey work behind us now, everything from here on in is 100% exotic vacuum plunger fun stuff, beginning with the ingenious Goossens spindle. We step up a gear in the next post, in which the beating heart of this mod is skewered onto the Control Rod.

Kaigelu 316 Plunger Filler: Parts and Tools

The Kaigelu 316 Vacuum Plunger filler, field stripped.

Tools Used

The only tools used were a mini drill with various attachment heads, cheap garbage circlip pliers, sparkplug pliers, standard pliers, a 42tpi craft saw, an empty reel of dental floss, and a couple of sheets of sandpaper.

A clean razor saw, ideal for meddling with nature's divine order.

Parts Used (UK sourced including domestic shipping)

• A 2mm diameter brass rod, £3.30 (for a 12inch/30cm long rod) from eBay seller CJW Steam.

• Three stainless steel external circlips, "to fit 1.9mm groove". £1.49 (for a 5 pack) from eBay seller globalengineeringmaterials.

• Two stainless steel internal circlips, "to fit 8mm groove". A pair for £2.49 from eBay seller look-now-more.

• Three M3x8mm rigid plastic washers, £1.35 (per packet of 10) from eBay seller tbwfasteners.

• Two 4mm ID, 8mm OD plastic pulleys "to fit 2mm shaft". £1.90 (for a 5 pack) from eBay seller birkada.

• A Sheaffer "Pen For Men" point seal gasket. £4.09 (for a 2 pack) from vintagepensacsandparts.com.

• A nitrile rubber O-ring, 5mm ID x 2MM C/S. £1.89 (for a pack of 10) from eBay seller Sealforce O-ring and Seals Solutions.

• An 8mm spring steel internal circlip, £1.69 (for 4) from eBay seller shiney-d.

• A gold plated jump ring. £1.00 for "10 grams of mixed sizes", from eBay seller diamonte-designs.

On Flounder's Mindthots next time...
With all that rattling around the parts drawer, the Kaigelu was strapped to a gurney and the experiment ready to set up, so let's charge the voltaic accumulators, scorn the laws of Creation, and begin Prepping for Surgery,  covered in the next post.

Kaigelu 316 Plunger Filler: Introduction

The follow on project to the vacumatic jumbo Hero 616 is complete! To disambiguate before the starter's pistol: This mod retrofits a modern Kaigelu fountain pen with a vintage Sheaffer or Onoto style single stroke vacuum plunger filler, not the unrelated Parker multistroke ink~pump with a similar sobriquet, as was the focus of last year's Hero based undertakings.
 

"Yes please."

This nib always makes me smile!

With TWSBI's release of the Vac700 last year, and the resurrection of Onoto's Magna, plunger fillers are currently a hot topic among fountain pen afficionados. As with Parker's vacumatic, there is a mountain of information available detailing the workings of this venerable design (the first Onoto plunger filler made its debut in 1905), as well as a surprisingly recent innovation that does away with the need for specialist seals.

Such a depth of detail brings the concept within an amateur's grasp; armed with a fistful of browser bookmarks, I couldn't resist trying my hand. This mod junks the Kaigelu's workaday cartridge/converter for the compelling gadgetry of a vacuum plunger filler!

In a departure from the spirit of the Hero 616 button filler and vacumatic conversions, for this project, I've adopted a more upmarket, "cash-rich, time-poor" ethos. Having said that, once installed, future servicing should be inexpensive as well as expedient.

The end result is a Kaigelu 316 with a more interesting filling system, increased ink capacity, and a more neutral balance in
 the hand. I've embedded a short demonstration clip of the completed pen below:

 The 316 Plunger Filler in action.

Quite pretty pens, these Kaigelus.

Why a Kaigelu this time around?

• Wow factor - if you're going to build a plunger filler into a modern cartridge pen, why not do it with some style! As a writer it backs up good looks with dependable performance. The 316 model is a decent Duofold doppelgänger, and the smooth two-tone nib even comes with medium tipping as standard. The one weak link is its problematic cartridge converter, which I can't get along with. This £14 beauty deserves a more interesting ink filler!

• I'm no mathemagician, but I suspect there's some sort of churlish golden ratio involved in building a working vac plunger (vacuum cylinder volume to release chamber volume, chamber volume to section feed volume and so on ad tedium). The Kaigelu 316 is huge, with a lot of space within the barrel to work with. We're talking "PFM point gasket as shaft end seal" huge. So I figured "touch wood and throw lots of space at it". The Kaigelu has space in spades!

• Unlike Hero's 616, the barrel is roughly cylindrical, which helps in retrofitting any reciprocating-seal ink filling system tremendously.

• The barrel wall thickness is positively Theodesian. I could bore into it for the mounting of interior circlips and hollow out the bottom vacuum release chamber without concern.

• The blind cap comes ready made! The end finial on the pen comes from the factory as a separate piece. This factor alone makes for a great time saver.

• The weight of the vacuum filler's extra brass and stainless steel helps alleviate the Kaigelu's wildly top heavy factory balance. Well, a bit.

A charcoal Kaigelu 316 on ice.

The subheadings below are pretty much in order of the build as it took shape, I think it makes for a fresher read to preserve a scatterbrained vérité in the write up of this mod. A Haynes manual style rearrangement of the component assembly would whiff of an omniscience that was entirely absent.

This Introduction - Scroll down for some more glamour shots of the finished pen, or click a subheading to skip ahead.
Parts and Tools - A list of everything used to make up the vacuum plunger filler and install it in the Kaigelu.
Prepping for Surgery - Discarding excess metal from the section and finial to max out the space available.
The Plunger Rod - Outfitting a brass rod with a pascal-variegating Goossens spindle.
Shaping the Seals - Turning down rubber seals to custom fit the Kaigelu.
The Packing Unit - Cutting the barrel's packing unit mounting grooves, making up the packing unit, and installation.
The Expansion Chamber - Hollowing out the lower barrel's vacuum release chamber.
The Blind Cap - Securing the blind cap to the plunger rod, and making up a snap ring for opening and closing it.
Further Mindthots - A few thoughts on future improvements, things I would do differently in hindsight, and so on.
Thanks, No Thanks! - Sources that aided this cartridge to plunger filler mod, and setbacks that hindered the project.


Photo Gallery
Here's some more photographs of the finished Vac316 to round off this introductory post. Click any thumbnail to zoom in.

One last picture before we roll up our sleeves - of the amazing pen that started it all!

Onoto poster courtesy of The Onoto Pen Co Ltd www.onoto.com

Next time on Flounder's Mindthots...
Parts and Tools used in the customisation of this Kaigelu.