Anyone have luck making friction fit section/nib unit interfaces?

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AdventiveIowa

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I’ve been wanting to make myself a brass fountain pen for a while, after seeing the pens by Karas Kustoms, but not really wanting to put down the money for the pen itself.

So I came up with the bright idea to turn the pen myself, I’ve got access to a metal lathe and I’m an engineer so naturally I think building something from scratch that I’ve never tried before should be easy (what hubris)

Anyways I ran into this forum while researching for the pen and after realizing that some of the taps and dies required for a kitless pen are expensive, I’m trying to see if I can make something work as a first pass with the equipment I have.

So with that in mind, I’m wondering if anyone has had success with friction fitting the nib sections into their pens. This would mean I wouldn’t have to buy a tap for the Jowo #6 I was thinking of.

Any thoughts are greatly appreciated.

-Hank


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FGarbrecht

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Are you talking about fitting the section to the body of the pen OR friction fitting a Jowo housing into the section? If the former you can just use a standard 9 mm tap/die set (not expensive); you would only need the custom Jowo tap/die if you are using a manufactured Jowo feed housing instead of making your own section. If the latter, I haven't tried it (friction fitting) but the tap isn't really that expensive (Cheng Wu here on IAP can get reasonably priced taps for you).
 

darrin1200

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Welcome to the forum Hank.

If you have access to, and a good amount of experience on, a metal lathe, then I think you should be able to make your own pen. A lot goes into the design and how the parts fit together, but being an engineer, this should be relatively easy for you.
A friction fit by its name is a smaller hole than the part being pushed in. If you squeeze the feed housing into the hole, it will likely squeeze the nib and feed causing issues (it doesn’t take much). You can create a friction fit hole for just the nib and feed, but it is not a round hole, and will take some trial and error to get one that works. Finally you could make a slip fit hole, for the feed housing, and glue it in place. This should work, and the only issue I can see is the relative difficulty in changing to a different nib.

Can’t wait to see your progress pictures.
 

More4dan

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Hank there are a couple options for what you are looking to do. You can make the ID for the section a slip fit for the JOWO #6 and glue it in, carefully. You can make your own tap using the threading capability of the metal lathe. Or you can order a M7.5 x 0.5 tap from Amazon of EBay that is a close enough fit for the JOWO #6. It will be 0.1mm larger but with a 0.5mm thread, the overlap should be enough. I’ve made several poor boy taps, let me know if you want to go that route and I can share how I did it.

Danny


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jalbert

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If you have access to a metalworking lathe, learn to single point thread. Then you will never have to buy taps and dies
 

FGarbrecht

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If you have access to a metalworking lathe, learn to single point thread. Then you will never have to buy taps and dies
Are you able to cut the internal section thread this way? Seems pretty challenging, not even sure my tiny internal threading tool could even get in there.... ;)
 

AdventiveIowa

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A friction fit by its name is a smaller hole than the part being pushed in. If you squeeze the feed housing into the hole, it will likely squeeze the nib and feed causing issues (it doesn’t take much). You can create a friction fit hole for just the nib and feed, but it is not a round hole, and will take some trial and error to get one that works. Finally you could make a slip fit hole, for the feed housing, and glue it in place. This should work, and the only issue I can see is the relative difficulty in changing to a different nib.
Ah, see this is exactly what I was worried about. I haven’t had a chance recently to take a good look at my nib units (all my pens are inked up and I don’t really feel like uninking them just yet), but I had a feeling they would require a non-circular hole in order to friction fit in. The reason I thought of this in the first place was I know some of my pens have a feed/nib that just slips in to the section (ex: Pilot Metropolitan), so I was wondering if that would be reasonable to attempt.

Also, now that I think of it, a friction fit probably works fine on the plastic sections because the plastic deflects evenly with the feed, whereas the brass is gonna be a lot stiffer and more likely to damage the feed.

With that (and the comments of others) in mind, I think I’ll put down the money for the special tap (I think I saw someone link Amazon for that specific tap) and do the rest with what I’ve got. If I get much more into this I may try single point threading with the lathe gearing in future, but that’s a whole different project.

Thanks for the advice everyone, I’ll keep you posted on progress.

-Hank


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Curly

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I was with my friends family at this mother in laws place one Christmas. She was getting rid of stuff to the family and the youngest of one of the aunts came away with a fountain pen. I explained to him how it they work because he didn't know what it was. I said I would like it if he decided he didn't want to keep it. He liked it because it was green and was keeping it. :( It had no branding on it as near as I could remember but the nib and feed pressed into the section. There was no housing. I figured it had to have a slight taper but without it I would never know how much. This thread reminded me of it so I went and had a look at a Bock 250 (#6 nib size). The feed has a slight taper of about .005" along the side. I don't have a nib handy put on it and measure that direction. The housing looks round except for the area where the nib would sit. I'd bet dollars to doughnuts that if you match the taper in your section the feed and nib would seat. The trick will be to measure accurately and bore the required taper into the section.
 

AdventiveIowa

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I'd bet dollars to doughnuts that if you match the taper in your section the feed and nib would seat. The trick will be to measure accurately and bore the required taper into the section.
Hmmm... I guess I’ll have to take a closer look at some of the feeds I have and see how confident I am in my measurements...

I guess the real answer to my question is that I need to get my hands inky and take apart a pen.

Thanks for the anecdote, I hope your nephew enjoyed the pen!

-Hank


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Curly

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My buddies nephew actually or I would have ripped if from his little fingers. :) It is probably sitting in a drawer someplace. You could just buy some of the nib, feed and housings in the brands and sizes you might want and check them. Ball gauges and micrometer time, callipers aren't accurate enough. You can check the dimensions and decide if you want to make a section with the feed taper or skip it and thread it for the housing. The real advantage of not using the housing is being able to make a slimmer pen section by a couple millimetres or so but it will add another level of complexity to making it.
 

jalbert

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I was with my friends family at this mother in laws place one Christmas. She was getting rid of stuff to the family and the youngest of one of the aunts came away with a fountain pen. I explained to him how it they work because he didn't know what it was. I said I would like it if he decided he didn't want to keep it. He liked it because it was green and was keeping it. :( It had no branding on it as near as I could remember but the nib and feed pressed into the section. There was no housing. I figured it had to have a slight taper but without it I would never know how much. This thread reminded me of it so I went and had a look at a Bock 250 (#6 nib size). The feed has a slight taper of about .005" along the side. I don't have a nib handy put on it and measure that direction. The housing looks round except for the area where the nib would sit. I'd bet dollars to doughnuts that if you match the taper in your section the feed and nib would seat. The trick will be to measure accurately and bore the required taper into the section.
The inside of the housing is not round either. There is a flat along the bottom of the interior of the housing to align the feed properly, and there is An arc cut out of the top of the interior to accommodate the curvature of the nib. These are things to take into consideration. I’ve messed with trying to set nibs and feeds, and I’ve had very poor luck with friction fitting modern ABS plastic feeds, since they don’t heat set like ebonite does.
 
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