In terms of preventing the nib from drying out and getting the best seal with the cap, is it generally considered preferable to have the cap seat against the shoulder of the section, or to have it seat against the end of the threaded section? (I'm new at this so hopefully that question makes sense. Seems like either of these would be an option depending on the way the cap is drilled.) I am using ebonite sleeves at the moment, but presumably the considerations would be the same for any material. Any other considerations that would argue in favor of one or the other approach? Thanks in advance for any advice.
Question regarding fountain pen construction
- Thread starter Jhecht
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Oliver X
Member
It should stop and seal on the front of the section. I'd argue that even if it could stop and seal against the barrel behind the threads, it shouldn't. If it seals against the front of the section, you have the smallest possible sealed volume. If the pen leaks from being jostled or whatever, there's no real opportunity for that ink to flow down the side of the section or into the threads, making a mess, unless or until the pen is uncapped. The lip of the cap is typically quite thin, and if you're not making oversized barrels and thick caps, putting stress on the cap lip can cause it to break. Honestly, for the typical turned pen with threaded cap, there's absolutely no reason not to stop and seal against the front of the section.
rixstix
Member
Can't help with the seat position question but there are other qualified turners to answer those specifics.
I've been testing a tapered, air tight, compression cap to body fit instead of threads. Haven't had a dry out yet. Nor have I had scratching issue yet.
I've been testing a tapered, air tight, compression cap to body fit instead of threads. Haven't had a dry out yet. Nor have I had scratching issue yet.
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duncsuss
Member
What Oliver said.
its_virgil
Member
Oliver is correct. It would be interesting know how many "bespoke, custom, kitless, artisan, etc" pen makers here make the cap seat against the end of the section. Just wondering.
Do a good turn daily!
Don
Do a good turn daily!
Don
PatrickR
Member
In my experience both ways work fine. I normally stop the cap on the barrel but have made some that stop on the section. I have not had any problems with drying out either way. As long as the joint isn't sloppy there is little chance of evaporation. I see many commercial pens that stop on the barrel.
it's more a design decision to me. if you want a step-less barrel it has to stop on the section and that changes the work flow and may require a different section shape. Best to be able to do it either way.
it's more a design decision to me. if you want a step-less barrel it has to stop on the section and that changes the work flow and may require a different section shape. Best to be able to do it either way.
Penchant 4
Member
Agree absolutely!
ProSingulisArts
Member
I read this last week about sealing against the section, I'll admit hadn't really thought about it but it makes sense.
For those of you doing this, is it very careful machining of the cap liner to make that happen?
Maybe I over complicated it but I have a cap liner with a threaded insert that can be adjusted down against the section.
Too much?
For those of you doing this, is it very careful machining of the cap liner to make that happen?
Maybe I over complicated it but I have a cap liner with a threaded insert that can be adjusted down against the section.
Too much?
duncsuss
Member
You already took it way further than I do by have a metal cap liner. I don't make many caps from wood, so they are typically a single material (such as cellulose acetate, acrylic acetate, galalith).
I drill as close as I can manage to the correct depth by hand/eye. I'm using a wood lathe, not a metal lathe, so the accuracy is limited, but there are always ways to compensate - an extra half turn on the cap threads, for example.
PatrickR
Member
My approach is similar but I made a dummy cap with an extended finial. I screw the finished barrel and section in with the desired number of turns, screw the finial down to it and that tells me where the stop needs to be.
Oliver X
Member
For pens where the cap overhangs the barrel, there is somewhat more tolerance as the exact position doesn't matter quite so much so long as there is sufficient clearance cut from the inside between the lip and the threads. For pens with a step between the threads and the rest of the barrel, cutting the shoulder in the cap too deeply will cause the cap to stop on the step on the barrel, whereas cutting it shallow will cause the cap to stop short and leave a gap. I use a metal lathe, so nailing the depth within a couple thousandths of an inch is pretty straightforward. I use a pair of calipers to measure from the front of the section to where I want the cap lip to sit and cut the shoulder to that depth.