Kitless Pens -- Brass Tubes Needed?

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EricRN

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May 16, 2019
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Hi all,

Quick question for those of you who create your own finials, etc. out of aluminum, ebonite, or some contrasting plastic: Any reason to include brass tubes or do you just drill out the material and glue/thread your finial to the body? I can think of only two reasons that the kits use brass tubes: First, I assume they are necessary or the friction fit of the components. Second, they might provide some stability for the pen body, ensuring that it doesn't warp or bend over time (as some of the older acetate blanks tend to do). Obviously, the first doesn't apply for a kitless pen since the aluminum would be threaded or glued.

But what about the second? Do you include a brass tube for structural purposes? If you don't, how thin do you think you could turn a blank while maintaining the structural integrity? I know that last question will vary depending on material and many other factors. But I'm just wondering how folks go about thinking through that issue.
 
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FGarbrecht

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Never used a tube in a kitless pen (autocorrect trying to change kitless to witless, maybe it knows something I don't), although I can see a possible advantage for wooden pens made with blanks that like to explode during turning (e.g. burls). I generally use hardwood burls or ebonite and don't worry too much about making walls as thin as possible. I get around the exploding problem (sometimes) using CA or stabilizing the blank beforehand; wall thickness for my pens so far is just under 1 mm or so for wood, 0.5 mm for ebonite.
 

hokie

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For my kitless pens made primarily from wood, I use brass tubes in the barrel, but not in the cap. I do it for the structural purposes you list, but I don't do any friction fitting. I just don't like to chance it by putting pressure on the wood. I do slip fits with epoxy for my components. I also like the brass tube, because I can use my closed-end mandrels made to fit in the tubes and I can finish the barrel before even adding any other components like the threads. If I could use brass in the cap, I would, but it's just easier to make the threads in the plastic liner material. Adding brass would just make the cap way too thick/stout. They are quite strong and haven't warped on me yet.
 

duncsuss

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Yes, I've used brass tubes (I buy the 10" or 12" long pieces) to give both wood (especially burls) and fordite structural integrity.

I picked a size that allows me to use a plug of ebonite or acrylic acetate that I can drill through and tap for the section to screw in. Just had to do a little experimentation and use the calipers to settle on a size that works for me.
 

skiprat

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I generally include brass tubes unless the pen is solid metal.. I believe that it adds to the structural integrity, esp if it is segmented.
I don't make many wooden pens, kitless or otherwise. I honestly can't see any benefit from not using a tube. There really can't be much, if any weight saving. I can't stand seeing plastic threads through a cap. A painted tube also hides the ugly translucent patchiness of many plastic blanks. Some pens that would otherwise be quite stunning, often look so patchy that you'd think they were made from different material for different parts. :)
 

Dalecamino

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Good question. I don't use tubes, or any other material to re-enforce the pen. I was taught to drill the lower body diameter just enough for the refill, or cartridge to insert freely. Same for the cap, and finial. Usually 1/4" for the refill, and 7/16ths" for the cap. The finial is drilled and tapped for 9mm. The completed pen is stable unless it's abused, which has never happened to me. Yet!
 

jalbert

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My philosophy, but you do you:
Tubes/other reinforcement: wood, natural materials (horn/antler), casein, polyester resin, tru stone (and similar brittle composites), whatever else takes threads poorly and has low tensile strength or the propensity to move

no tubes: acrylic acetate, celluloid, cellulose acetate, lucite, stable resins or other materials that thread well, metals, anything you want to be transparent and be able to see through.

I say "other reinforcement " because I've never used tubes per se, but rather incorporated the structural liner into the rest of the pen.
 

magpens

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So ... what I am reading here is ... it all depends !!

Use tubes if, in your judgment, you need 'em. . Don't use tubes if, in your judgment, you don't need 'em.

That's my philosophy also.

Sometimes my inspiration for a kitless pen might come from a kit pen. . So sometimes my "kitless" design begins with tube(s), and over the course of the project development I come to the realization that the tube(s) can be left out so I leave them out.

One of the benefits of leaving out tube(s) , as Chuck said above, is that you can reduce hole sizes to almost the minimum to accommodate the innards (such as refill, ink cartridge, pump, or whatever). . And having the thicker material as a result assures structural integrity in the absence of tube(s).
 
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Pierre---

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When I use straight grained hard and heavy wood, I am not sure a tube would enforce it. First, such a wood is already very strong, second I am afraid of cracks coming from the difference metal and wood behave as far as dilatation is concerned. I prefer to thread the wood, sometime I make an acrylic or ebonite sleeve in the cap for the nib not to dry too quickly. I made several snakewood pens that did not crack, I would say because they had no tubes.
 

darrin1200

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I sleeve any porous or unstable material. Usually with ebonite or alumilite.
As mentioned above, it can add strength and threadability, along with creating a sealed chamber to prevent the ink in the nib from drying. (90% of my pens are fountain pens.)
I also create a stepped lip in the cap to seal the nib in an even smaller chamber.
 

FGarbrecht

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I sleeve any porous or unstable material. Usually with ebonite or alumilite.
As mentioned above, it can add strength and threadability, along with creating a sealed chamber to prevent the ink in the nib from drying. (90% of my pens are fountain pens.)
I also create a stepped lip in the cap to seal the nib in an even smaller chamber.
Do you cast the alumilite in a predrilled hole in the cap or do you fit an alumilite rod into the hole?
 

hokie

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Do you cast the alumilite in a predrilled hole in the cap or do you fit an alumilite rod into the hole?
I'm not who you asked, but for the sake of contributing to the conversation, I typically make a sleeve already turned and threaded to be inserted and glued into a pre-drilled hole of a square blank. Looks something like this:
1608247376269.png

Once the epoxy is cured, I use a threaded mandrel to shape the square blank into the final shape and finish of the cap
 
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