The section, at its simplest, is a tube that holds the nib and feed and contains the flow of ink from the reservoir to the point. It was originally known as the gripping section, not because that’s where we grip the pen (not everyone holds it so far down) but because it gripped the nib and held it in place. All but the occasional pedant calls it just “the section” now.
The first sections were tapered to accommodate a slip cap, and had a screw fitting to enable access for filling the eyedropper pen, and to seal it against leaks when closed. They were invariably hard rubber, which machines well, and the threads on traditional eyedropper pens are usually extremely well cut and remain ink-tight today. Some people apply silicone grease as a sealant but it’s seldom necessary. It will do no harm and may make unscrewing the section easier, but additional sealant is rarely needed. These early, tapering sections are often quite thin-walled, and it pays to treat them with care. Some, like the early Swans, will have slits in the section to accept the nib.
Swan was early in the field with a screw cap, and the section had to change to meet its needs. It’s still an eyedropper filler, so it, too, has the screw fitting to the barrel, but now the end nearest the nib swells out to provide a flat face, which makes a positive seal against the inner cap.
The next development changes the section to attach to a sac by a peg or nipple at the rear of the section. The “step” at the front of the section to meet the inner cap has become more accentuated. This form of section will remain unchanged for several decades. The nipple is the most fragile part of the section, and cleaning it of the remains of an old sac should be done carefully. If you should be unlucky enough to break the nipple on a rare section for which you can obtain no replacement, do not despair. They can be repaired, though it isn’t a job for the novice. Professional restorers can do it for you.
Even after hard rubber was superseded by celluloid for barrels and caps, most sections were still made from hard rubber. There were several reasons for this: it machined well, and sections have to be made to a fine tolerance. It is less brittle than celluloid and has some “give”, a necessary attribute, given the fact that a section is always containing the pressure of a nib and feed which are essentially wedged in place. Hard rubber sections contain that pressure well, but they do distort over time, ovalling slightly where the edges of the nib meet the section. For this reason, it’s a good idea, before removing the feed and section, to mark with a pencil where the centre-line of the nib is. Replacing the nib in exactly the same place will be much easier.
Sections come in for quite a bit of abuse. They are often quite difficult to remove from the barrel, and undue force may be applied with inappropriate tools. That’s a recipe for disaster, of course, and heat is your friend in removing sections from barrels. That, and a lot of patience. If you must use pliers, use ones with rubber on the jaws. Don’t use excessive force; it will free up after repeated applications of heat and moderate force. Never remove the nib and feed while trying to remove the section. Leave them in there, as they provide internal support for the section and prevent it from being crushed or cracked.
Some sections have a press (friction) fitting, some are screw-in. You’d think there would be some some kind of logic to which type was used for which purpose, but it isn’t so. Certainly, ink-in-the-barrel pens like eyedropper fillers and Onoto plunger fillers invariably have screw-in sections to contain the ink. Logically, button-fillers should have screw-in sections because they have to resist downward force from the pressure bar, and lever-fill pens should be friction fit as they don’t have any pressure to deal with. Would that it were so simple! Many button fillers are friction fit. It’s the cheaper fitting method, and, in truth, the force a button-filler’s section has to contend with is not that great. Then there are pens like the Parker Televisor that use the Parker anchor pressure bar which transfers the force to the barrel end, rather than down to the section. They have friction fit sections.
Surely, though, there’s no need for a lever filler to have a screw-in section? That’s right. There’s no real reason for it, but they do. Many Swans and Wyverns have screw-in sections, perhaps because they were seen to be an indication of quality, perhaps to reduce the number of different parts that were being manufactured. Just to make it even more difficult, some Wyverns have a left hand thread! You never know what to expect when trying to remove the section from an unfamiliar pen, so proceed with caution.
When pens like the tubular-nibbed Sheaffers and the Parker 51 came along, the design and even to some extent the purpose of the section began to change, as did the nomenclature, as that area of the pen became the “shell” or the “hood”. There were other changes, too, to accommodate the plastic cartridge, but all these interesting developments fall outside this discussion of the section.