Twist fillers are easily mistaken for piston fillers, as both sorts have a knob at the end to turn for filling. However, twist fillers will take it highly amiss if you crank them around in the same way as a piston. These pens work by wringing the sac to compress it, and too much wringing is always a bad thing.
There are two main ways of achieveing this effect. The simpler sees both ends of the sac attached to the pen– one at the section, the other to the filler knob. The slightly more complex has a rod on an eccentric cam which entangles a sac which is otherwise like that in a lever or button filler.
This is a very simple filler to use, requiring not more than a single turn of the knob to complete the cycle, but it was never widely used. One suspects over-wringing as a constant menace to both the user’s clothes and the maker’s warrantee costs had a major role in this. Many pens with this sort of filler will have a warning of some kind imprinted upon the knob, but given how well people read instructions, this would have been of limited use, and in some cases the instructions were misleading. As an example; Wahl offered for a while a hybrid of bulb and twist filler, on which one was told to turn five times. By this it meant to work the twist mechanism five times, as making five full rotations would tear the sac from its mounting and do huge mischief to other parts of the mechanism.
The only real advantage of this sort of filler over the other sac-based sorts is that there’s no mechanism inside the barrel taking up ink-space… except in those versions where there is. They’re a little cantankerous for repair, and there is the worry about over-twisting. They’re also pretty uncommon, so there’s a good chance that if you have one you already know your way around a vintage pen.
Loading a Twist Filler Step by Step:
- Get a paper towel or other pen-wiper.
- Remove caps from pen and ink bottle.
- In some models, the knob for the mechanism is concealed under a blind cap which must also be removed.
- Immerse point in ink.
- Turn the knob; if it does not have a built-in stop, do not turn more than 360° and if there’s substantial resistance before you’ve turned even that far, stop.
- If you have a Wahl Oxford as described above, repeat this step four more times.
- Remove pen from ink and wipe point and section (aren’t you glad you did step 1?).
- Replace caps.