# Spring loaded cartridge converters



## Penultimate (Aug 10, 2022)

Greetings
I was looking for a syringe for filling the cartridge of my Pilot Parallel pen. I found what I was looking for at Anderson Pens and a Con 40 converter. However, I found these spring loaded cartridge converters on Amazon. They are the same size as a regular converter and  hold about the same amount of ink. I find them easier to use. They also come with a blunt needle and coupler for a syringe.


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## duncsuss (Aug 11, 2022)

These look interesting for another reason - it looks like they are a uniform diameter along the entire length, unlike regular twist-style converters which usually have a wider collar around the screw mechanism.

I have a couple of kit pens where the regular converter doesn't quite make it through the threaded coupler that the section screws into, these might work.


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## monophoto (Aug 11, 2022)

There are many filling mechanisms used in fountain pens.  These 'spring loaded converters' are an example of a plunger filling mechanism. Pressing the plunger expels liquids and air from the reservoir, and when the the plunger is released, the spring causes it to return to the extended position while drawing ink into the reservoir.  Sunt multi modi ut felem pellis - there are many ways to skin a cat.

But I'm puzzled about the reason for including a syringe coupling.  If the syringe is used to fill the converter, then there is no need for the plunger and spring.  Conversely, if the plunger and spring are used, there is no need for the syringe and coupler.  

Cleaning?  Don't think so - the plunger/spring will do a fine job of flushing out the reservoir if it is actuated in a container of water.


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## duncsuss (Aug 11, 2022)

monophoto said:


> But I'm puzzled about the reason for including a syringe coupling.  If the syringe is used to fill the converter, then there is no need for the plunger and spring.  Conversely, if the plunger and spring are used, there is no need for the syringe and coupler.



The syringe needle is useful for getting the last millilitre of ink out of a bottle.

Decouple the converter from the section, attach the needle, and you're able to get right down into the corner of the bottle to slurp up the remaining droplets - which would be impossible with the converter still mounted in the section, and a lot harder with just the converter pushed into the bottle neck.

Pineider make one which looks fancier than this, but in my experience doesn't actually fit a standard international converter so that was a waste of $20.


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## Penultimate (Aug 11, 2022)

Duncan
The small diameter is 0.195  inches, the larger diameter tapers from 0.278 to 0.302 by the red part. Hope this helps


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## Penultimate (Aug 11, 2022)

Louie
Duncan said it better than I could. I found while searching for syringes. I’m not sure if they would come up as converters. 

This is kinda of a small point but I thought a plunger filler was a filling system where the plunger was pressed down and a vacuum was drawn behind the seal. When the seal hits a relief at the bottom of the stroke ink flows up into the reservoir. A syringe filler is what you described and what these spring loaded converters are. Just asking because I like to get my terms correct. I’ve made two syringe fillers and am making my second plunger filler now. 

Clear plunger on the right, blue syringe on the left. 
Thanks


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## duncsuss (Aug 11, 2022)

Penultimate said:


> Duncan
> The small diameter is 0.195  inches, the larger diameter tapers from 0.278 to 0.302 by the red part. Hope this helps



Thanks - I just measured my regular converter at 0.304, so there's really nothing in it. I might still buy one just to get the needle, I resent paying good money for ink I can't write with


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## monophoto (Aug 15, 2022)

Mike

Don't want to haggle over terms, but a 'piston fill' and 'plunger fill' are two names for the same generic filling principle - in either case, a plunger forces a piston into the reservoir to expel air and any remaining ink, and then when the plunger is withdrawn, the piston creates a vacuum within the reservoir that draws in ink. That mechanism can be built into the pen body (as in the case of the Noodler's Konrad where there is a small cap at the end of the body that is removed to access a twist knob), or it can be part of a removable element called a converter or pump, in which case the entire body is removed to access the knob.  And while a twisting knob is the most common approach to actuating the piston/plunger, it can also be actuated by means of a slider (most often seen on inexpensive Chinese pens) or it can be a spring-loaded press-in plunger.

The fact that the piston/plunger fill principle creates a vacuum in the reservoir to draw ink into the pen can lead to confusion with another form of vacuum filling.  One of the early filling mechanisms involve a small rubber sac that served as the reservoir, and a lever on the outside of the pen body that pressed a plate against the sac to expel air.  Then, when the lever was released, a vacuum would be created that drew ink into the sac.  A later variation on this principle was to replace the external lever with an internal sleeve around the sac - the user has to remove the pen body to press a flexible portion of this sleeve against the sac.  This innovation may have first been used by Parker (I have a  mid-1960's era Parker model 45 that uses this kind of fill), but it's still being used by some Asian pen makers such as Hero who specialize in Parker clones.

Syringe filling, by contrast, is a design wherein ink is injected into the pen using a syringe.  An alternative (and older) name for syringe filling is eyedropper filling.  This principle dates to before modern filling mechanisms were invented when users had to literally use medical eyedroppers to fill their pens.  Syringe filling requires that the body of the pen itself be sealed since that body, in its entirety, is the ink reservoir.  Because the body is the reservoir, syringe fillers are known for having enormous ink capacity.  While there may be some pens that are manufactured and sold specifically as syringe fillers, it's probably more common for pens designed for cartridges and converters to be converted by the end user who has to use some kind of some kind of sealant, often silicone grease, to minimize leakage.    For example, the inexpensive Platinum Preppy is a popular starting point for syringe conversion.

Plunger/piston filling can't completely fill the reservoir in a pen, and the circle closes on itself when a syringe is used to 'top off' the incomplete fill left by one of those principles.  So a piston/plunger fill become a syringe fill, and the words start to lose some of their unique meaning.


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