Are the hoods of Parker51 Vacumatic and Parker51 Aerometric the same?

[MiroG]

Are the hoods of Parker51 Vacumatic and Parker51 Aerometric the same?

[guyy]

No they are not

[pajaro]

This is an interesting question. It never occurred to me to use a Vac hood on an Aerometric pen or vice versa, because the colors don't track from one to another, but I don't know about Vacumatic India Black and the aerometric black. Good to know, though, that the hoods won't interchange.

[Farmboy]

I would say it is not so simple as they are different and will not interchange.

[fountainpenkid]

Isn’t there a difference in the way they seal with the connector?

[Ron Z]

I would say it is not so simple as they are different and will not interchange.

Well, they can. I've seen it done. The thread pitch and diameter are the same, though its true that colors are different. But on a black pen, who cares.

The 0-ring is the issue. Vacs don't have them, most aerometrics do. Threads on most aerometric connectors stop a little sooner on the inside end, in front of the clutch ring, to make room for the 0-ring. If you don't use, or don't need an 0-ring, they can be swapped out, but you have to seal the threads with either shellac or thread sealant. I assume that over tightening an aerometric hood without an 0-ring could crack the hood because the edge is thicker. But again, I've seen them used on vac 51s.

[pajaro]

Those interchanges should make some interesting color combos. I remember passing on a plum aero 51 with some kind of brownish burgundy hood. It looked a little odd, but I can sympathize with someone trying to find a plum hood. I am surprised that 51s are common with O-rings, Hardly any of my 51s have O-ring hoods, but then I bought most of my 51s in Florida (Pensacola).

[Farmboy]

Finally we have proof that Florida had a prohibition on o-rings!

The o-rings appeared a few years into the Aerometric age.