I successfully fettled and cleaned this Optimus 300. Any guess as to when it was manufactured?

@Jacob van Pareen
As I learned from @Nils Stephenson in THIS post your control wheel at least is of 1950’s date. So was mine (only the control wheel) but the rest of my lamp was from the 1930’s. Your photo doesn’t show the filler cap/air screw combination but that could be a dating element, along with the diameter of the pump knob (less than 25mm suggests newer).

 

A well built lantern.

 

As @presscall mentioned, some more photos will help. Is the top in one or two pieces? i.e. do the screws for the top cap hold the inner hood together with the outer hood.

 

Thanks for your helpful feedback Presscall and Nils.
The pump knob is 22 mm in diameter.
The inner hood is separate from the ventilator, like a Petromax.
I attach photos of the fillet cap and pump knob.

Many thanks,
Jacob.

 

I think I can just make out the edge of a level gauge. That would make it the last of the variations of the Optimus 300 with this style of writing on the tank. This variation usually has a black enameled top cap, but the next version had a nickel plated top cap. This could mean that it is right at the end of production of this variation. Probably early 1940s.

The wheel is most likely correct for the lantern. This variation can be found with wheels that have a slightly mottled effect and others that are slightly darker, but all basically the red/brown colour. For some reason the next version of the 300 went to the bright red wheel before going back to the brown colour for the 300P.

 

Thanks Nils.