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PM Bannatyne - a little reverse thinking



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GeoffMartin

At the heart of this pen is a "Churchill" kit, however, the only thing left from that is the feeder and section. I've put a Bock extra-fine nib in there, and made the rest myself on metal and wood lathes.

 

The cap and the top of the barrel section are turned from a rod of solid brass. The rest of the barrel is sustainably-sourced grenadilla (a.k.a. African blackwood or mpingo).

 

This one's a proof-of-concept / prototype for a new idea (at least, new for me).

 

Normally, the 10 x 0.8 triple thread for the cap has the exterior threads on the barrel, below the section, and the interior threads in the cap. This results in quite a long cap, since it has to extend far enough down to cover the nib, section, and grab the threads below. In this pen, I reversed these, so the exterior thread is on the cap, and the interior thread on the barrel. This meant that I had to turn the kit section down to accommodate the cap sliding in between it and the interior of the barrel, but there's plenty of wall thickness in the Churchill section to be able to do this.

 

20201231-173224.thumb.jpg.59faed6d7fc771d770c0116f718f6b87.jpg

 

The final result is a little top-heavy when capped (the pen, uncapped, is 19.5 g, and the cap by itself is 17.5 g...)

 

20201231-173100.thumb.jpg.a42920cc1feb4c0c05123eb625bc2e5c.jpg

 

This one's got a bit of a rough finish, since it's just a prototype. The plan is to use it as a daily pen for a couple of weeks to see if I need to change the balance before having a go at the "real thing". 

 

Cheers

-geoff

 

 

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Inspector

Interesting idea and execution. What is the diameter of the area you grip? 12mm or so?

 

Pete

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GeoffMartin

the whole pen is 12.8 mm in diameter, which is a little thick relative to the #6 nib. However, as grips go, it's a little under the 13.1 mm diameter of my MB 129, which I really like.

 

I'm already thinking that I'm going to get a little tired of the straight-walled, polished grip. The next version will probably need something like some grooves, knurling, or a little concave curve to help out...

 

Total weight : 37.1  g
Body weight : 19.5 g
Total length : 126.5  mm
Total length(with cap): 134.0 mm
Barrel max diameter: 12.8 mm
Cap max diameter: 12.8 mm

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SoulSamurai

I like it! I'm a huge fan of pens with completely smooth bodies (including no step or screws between the grip and the body), so I really like the way you've got a screw-on cap without any exposed threads!

 

I love the idea of knurling the grip; I do tend to have a bit of difficulty with smooth metal sections as I find them a touch slippery, but I really enjoy finely knurled metal sections as I find the texture and grip are pleasing (I actually went through a period of buying up all the affordable fountain pens with knurled grips I could find).

 

Actually a pen with a wooden body, knurled grip, and no threads or step sounds amazing to me - it checks all my boxes! If you were to sell a pen like that I would be very interested!

 

BTW if you find the pen has balance issues, perhaps a lighter metal like aluminium or even titanium could help?

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GeoffMartin

Thanks! Good idea regarding using Al or Ti... I was thinking more along the lines of just cutting the brass thinner. I don't really care about the mass of the cap, and the jury's still out on the pen for writing. I'll give it a week or so, and then turn some grooves in the brass to see if that helps. I could even make up some story about the design of the grooves being reminiscent of the fins in the feeder - but I don't sell pens, so I don't need to invent stories like this. 😉

 

Cheers

-geoff

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sansenri

Looks very nice, and I share with SoulSamurai the appreciation for the smooth grip with no steps or threads, interesting idea moving the threads on the cap.

 

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BrassRatt

I'm curious about "top-heavy when capped".  I seldom hear concerns about end-heaviness when a pen is capped, but lots of discussion about balance for writing when posted.  So, ...

Does this pen post?  Did you put internal threads on the back end of the barrel to allow this? 

 

Overall it's a design wow. I wonder if it would be possible to make this design without the brass "grip section" collar, but just put the threads inside the wood barrel for a total wood experience when writing unposted?

 

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GeoffMartin

Hi BrassRatt,

 

The problem with being top-heavy when capped is only a problem if you put your pen (upright) in a shirt pocket. Otherwise, I agree, it's not an issue.

 

I didn't thread the back end of the barrel, since this would be a hole that I don't want there - and the weight of the cap alone is almost equal to the weight of the pen, making it very back-heavy and weirdly unbalanced. I never post my pens anyway (with the exception of my little Kawecos) so this is not an issue for me.

 

As for your last point: I'm currently making two more prototypes. One will have less brass showing on the end of the barrel. More of a ring than a collar, so the grip is the wood instead - just as you suggest. I need a little brass to protect the end grain, but a couple of millimetres will do.

 

The second prototype will have the same dimensions as the current model, but with a sand-blasted brass instead of polished. It won't be as shiny, but it won't be as slippery either.

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GeoffMartin

The latest version:

This is the same pen after sandblasting the brass grip, with an attempt to make a gradient effect to the polish at the top of the cap. The slip problem is fixed. The new problem is that my son saw it and said "Dad, that's my favourite pen of all the ones you've made." So, I couldn't say no to his next question. Now I need to make a second one for me...

 

20210116-163918.thumb.jpg.07c6cdd0a89ff4f485259ed5dcecebcd.jpg

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SoulSamurai

What improvements are you planning for the next one? Would you consider adding a pocket clip?

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GeoffMartin

Hi SoulSamurai,

 

Maybe - although I doubt it (in spite of (or maybe because of) what I mentioned above on the top-heaviness of the pen when capped).

 

I prefer roll stops over clips on the pens that I make myself, although I'm starting to think about off-center weighting or faceting as the next challenges for me.

 

The sandblasting has also given me some ideas as well. This was my first attempt at sandblasting, and I'm starting to think that maybe this could be used to etch a pattern in the surface instead of a simple gradient. Sandblasting the wood could also be interesting - particularly if I use a wood with varying density / hardness.

 

So many new directions to try! 🙂

 

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GeoffMartin

Thanks! there are plenty of my old ones on my website at pm-pens.com.

 

This is shameless self-promotion, but not advertising, since I don't sell any of them - they just pile up in a drawer in our house... 🙂

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