In the 1950's, Montblanc came up with a piston filler popularly known as the "Telescopic Piston Filler". Pens made in that era which come with this filling mechanism are extremely sought after. This was an innovative design and what I consider to be an engineering marvel. Conceptually, it is not very difficult to understand how the filling mechanism works. However, it is very challenging to implement this design. It is believed that Montblanc discontinued making them because of the production costs.
When I first saw the telescopic piston filler, I was intrigued. I decided to make my own so that I can offer them on my pens. The detail of parts involved in making this filling mechanism is daunting. With limited capability to manufacture parts (essentially a mini lathe is all I have), I had to be innovative about how the telescopic mechanism is implemented. It took me months of research and several trials and failed attempts to finally make a Telescopic Piston Filler that works.
Most of the parts of this mechanism are made in brass. As a result, it does provide substantial weight to the body of the pen. The mechanism itself weighs about 22 Grams. The piston extends beyond the barrel threads so that the seal can be replaced easily. I use a delrin nut to secure the seal in its holder.
The seal can be either made in cork or an 'O' ring holder. A cork seal has to be made carefully to ensure that it provides just enough tension inside the barrel. If it is too tight the piston will disengage prematurely. While operating the piston, it has to be backed up against the section, so that it can fully retract while being filled.
Typical ink capacity of a pen fitted with this telescopic piston filler will be about 2.5 ml. This can be increased by making a longer piston. The brass insert nut that engages with the end cap is about 12mm diameter. Because of the size of the piston filler, the resulting pens will be slightly oversized.
This was a fun and exciting experience. Hope it excites others as well.
When I first saw the telescopic piston filler, I was intrigued. I decided to make my own so that I can offer them on my pens. The detail of parts involved in making this filling mechanism is daunting. With limited capability to manufacture parts (essentially a mini lathe is all I have), I had to be innovative about how the telescopic mechanism is implemented. It took me months of research and several trials and failed attempts to finally make a Telescopic Piston Filler that works.
Most of the parts of this mechanism are made in brass. As a result, it does provide substantial weight to the body of the pen. The mechanism itself weighs about 22 Grams. The piston extends beyond the barrel threads so that the seal can be replaced easily. I use a delrin nut to secure the seal in its holder.
The seal can be either made in cork or an 'O' ring holder. A cork seal has to be made carefully to ensure that it provides just enough tension inside the barrel. If it is too tight the piston will disengage prematurely. While operating the piston, it has to be backed up against the section, so that it can fully retract while being filled.
Typical ink capacity of a pen fitted with this telescopic piston filler will be about 2.5 ml. This can be increased by making a longer piston. The brass insert nut that engages with the end cap is about 12mm diameter. Because of the size of the piston filler, the resulting pens will be slightly oversized.
This was a fun and exciting experience. Hope it excites others as well.
Cool. What are the pens models that comes with this filling mechanism?
ReplyDeleteYes would live to have one with such piston filler
ReplyDeleteWhen are we going to get some pens with this piston
ReplyDeleteI'm intrigued , great work, congratulations ! Would you sell me one of your telescopic fillers ?
ReplyDeleteFrancis
I'm intrigued, great job ! would you sell me one of your telescopic fillers ?
ReplyDelete