"Portholes" streamline GF piston filler MB149 size

[fountainbel]

Hi fountain pen friends !

I could not resist , and decided design and make a MB149 size streamline ” Porthole GF piston filler”

I’ve used my very last Tibaldi Impero for this pen, just 2 cm of the celluloid was left when the parts were finished.

The section  is 21mm long, and the length of the front of the section to the barrel diameter transition is 31mm .

Doing so one does not feel any ergonomic drawback from the diameter transition during writing.

There are again 4 portholes - 180° apart - and given the 4 leads thread, this makes  the portholes are always perfectly aligned with the nib and clip.

Note the portholes are somewhat condensed after I’ve tested and flushed the pen, but they are crystal clear !

The cap shape is only  slightly  convex, limited by to the wide "wing width" of the vintage MB149 nib I wanted to install, which implies the need for a larger inner bore of the cap..

I’ve used my standard ball clip, and  made the ball resting on the silver ring, avoiding possible contact damage on the celluloid.

As always your comments and critiques are most welcome !

Best regards from Flanders,

Francis 

[es9]

1 hour ago, fountainbel said:

As always your comments and critiques are most welcome !

 

What's there to critique!  It's beautiful! 

 

Did you find this was easier or harder than working with rod-stock?

[Detman101]

Oh wow, that is too kewl!!

Definitely something that should become an industry standard!
Would be AMAZING with a polka-dot themed pen!

[como]

@fountainbelCongratulations, Francis! I don't think there is anything more to desire in a pen than this, the material, the nib, the design and historical background, craftsmanship, mechanical precision. Stunning!👍

[mizgeorge]

I've now had to come back three times to look at this thread. Beautiful. Just beautiful. I love the technical drawings too. 

[amberleadavis]

BEAUTIFUL

[fountainbel]

23 hours ago, es9 said:

 

What's there to critique!  It's beautiful! 

 

Did you find this was easier or harder than working with rod-stock?

Thanks es9 !

All my pens are made from rod stock....

I assume you refer to the difference in making portholes ink windows compered to making  a classic ink window ? Making portholes surely is more delicate  !

Francis

 

[Detman101]

I have to admit that the engineering plans are absolutely amazing!!
To get a glimpse of how the final product came to be....just stunning!
To see that level of technical expertise, planning and execution that goes on behind the scenes is really awesome.

[fcarbon]

As always Francis, incredible work ...

And a very plain down to earth question ... Which pencil (grade) do you use for drawing? 😉

Thank you for sharing and greetings!

[fountainbel]

8 hours ago, fcarbon said:

As always Francis, incredible work ...

And a very plain down to earth question ... Which pencil (grade) do you use for drawing? 😉

Thank you for sharing and greetings!

Thanks for your comment  !

Drawing was made on "mylar"  using Pentel 2H - 0,5 mm "high polymer" leads.

[zaddick]

This is one of the best Impero pens I've seen. What an great use of the last of a treasured celluloid.  Bravo! 

[fountainbel]

On 5/2/2021 at 10:43 AM, zaddick said:

This is one of the best Impero pens I've seen. What an great use of the last of a treasured celluloid.  Bravo! 

Thanks Zaddick, coming from a perfectionist as you are, this is a great compliment for me!

[Hardy08]

Truly gorgeous ink window, funnily I planned to add a similar one to my next pen, which is still on the lathe unfortunately...

Thanks for sharing!

[rajayk]

Very nice to see the last of your impero being put to good use Francis. I love the step down from the barrel to the grip section, and have always wanted to have the incorporated in a custom pen. Do you have a telescopic piston on this one or your homegrown piston? 

[Nurmister]

This is very pretty. But I wonder: why did you put the clip ball in the same position as the cap band? I would think they would damage each-other over time, especially if the pen was clipped and unclipped from pockets.

[fountainbel]

2 hours ago, rajayk said:

Very nice to see the last of your impero being put to good use Francis. I love the step down from the barrel to the grip section, and have always wanted to have the incorporated in a custom pen. Do you have a telescopic piston on this one or your homegrown piston? 

Hi Rajayk,

Thanks for your reaction !

This pen is equipped with the compact " long stroke"  piston filler of my own design 

This filler can nearly take as much ink in as the famous Montblanc telescopic filler.

Best regards,

Francis

[como]

1 hour ago, Nurmister said:

This is very pretty. But I wonder: why did you put the clip ball in the same position as the cap band? I would think they would damage each-other over time, especially if the pen was clipped and unclipped from pockets.

I would imagine that that can be said with ball clip that rests on the cap directly too, probably even more so because it's metal on plastic (resin, acrylic, celluloid etc).

[Nurmister]

7 hours ago, como said:

I would imagine that that can be said with ball clip that rests on the cap directly too, probably even more so because it's metal on plastic (resin, acrylic, celluloid etc).

 

Yes, haha, I was thinking that as I sent the post. And Francis did note that he wanted to avoid wear on the celluloid, so I suppose it's a matter of what you want to damage least. As long as the ring isn't plated then it should be no issue to polish any wear off. It's interesting we don't really see this design on many other pens, although even my older pens (none celluloid) don't have much wear from the end of the clip resting against the plastic.

[como]

1 hour ago, Nurmister said:

 

Yes, haha, I was thinking that as I sent the post. And Francis did note that he wanted to avoid wear on the celluloid, so I suppose it'a a matter of what you want to damage least. 

I see these ball clip scratches a lot on vintage pens. When a pen gets used as a pen is designed for, over time this becomes unavoidable. The ball on the clip leaves little dents or linear scratches. They are usually not bad, except when the plastic is deformed due to heat or whatever else, then you see a small crater! 

[fountainbel]

11 hours ago, Nurmister said:

This is very pretty. But I wonder: why did you put the clip ball in the same position as the cap band? I would think they would damage each-other over time, especially if the pen was clipped and unclipped from pockets.

Thanks fo your reaction Nurmister (

Both the capring and the clip ball are made from "cold rolled" sterling silver.

The cold rolling process  makes the surface more dense,  hence creates a  hard surface layer, reducing greatly the risks of wear.

Francis