Optimus No.1S c.1912-14

Discussion in 'Optimus No:1(inc. S & J)' started by igh371, Jan 7, 2017.

  1. igh371

    igh371 SotM Winner Subscriber

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    DSC05130.JPG
    An early example of the Optimus No.1S model. The '1S' 'economy' (cheaper) addition to the Optimus model range seems to appear for the first time in the 1912 catalogues, but by 1915 these stoves are shown with feet on the legs, hence an age guesstimate of dating this one between 1912 to 1914. Unlike the contemporary original No.1s the 1S does not feature the word PATENT on the tank top. The burner and pressure release screw both appear to be possible later replacements, unless the budget models were still being fitted with plain end legs after the 'main' models were given feet; in which case the stove itself may possibly date to as late as c.1917/8. The details of the base stamp and filler lid may prove significant in resolving this question at some point in the future.

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    DSC05145.JPG

    @OMC
     
  2. OMC

    OMC Subscriber

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    Hi Ian!! Another old beauty!
    Ya tagged me.... I got nothin'. Others have attributed changes occurring to all No.1s & 5s at same time, you may agree that we see exceptions to that. This one for example is a real head scratcher (thank you). You're thinking "feet" were given the economy versions at same time as the No.1, or maybe not? I'd agree later burner adds nothing definitive, for me either.
    Tank lid: certainly (even among just the flat tank lids), your tank lid is exceptional. It's without precedent for now (none like it in SRG on 1s / 5s), so for now tank lid may tell us little as to timeline (guess: "looks" earlier vs later, to me). Note 1. I like your "c1912-14" fine but if that expanded would not surprise either.
    Bottom stamp: see note 1. and it is early, among the similar, for yours we note M in Stockholm, the 2 sides of M are parallel (vs splayed at bottom).
    It's a head scratcher and has made an impression (esp lid) and more details may arise. thx omc
     
  3. igh371

    igh371 SotM Winner Subscriber

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    Some further thoughts on dating this external NRV Optimus 1S: the dilemma is that, all other things being equal, the overall presentation of the stove, including the filler cap, pressure release screw, tank markings and burner, all, to me, point to post-1915, possibly as late as c.1917/8. On the other hand there is no catalogue evidence of the continued use of plain -cut leg bottom ends in 1915 or later. Now, to consider the legs in more detail, here is this problematic '1S' in the centre with a c.1920 internal NRV Optimus No.1 to the left and a pre-1915 external NRV Optimus No.1 to the right:
    DSC05159.JPG

    Both the leg length and bottom end shape on the '1S' in the centre are closer in form to the later version on the left than to the early No.1 on the right:
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    On the other hand the shaping of the leg tops on our '1S' is clearly very different to that on the c.1920 stove (above), but identical to that found on the pre-1915 stove (below):
    DSC05161.JPG
    A further point of comparison can also be made in relation to the pump rods. The pump rods on the early external NRV Optimus No.1s are made of brass 4mm diameter brass rod, whereas the pump rod on the '1S' is considerably beefed-up being of 6mm round steel:
    DSC05165.JPG
    The 6mm steel rod is the same specification, though for obvious reasons longer, as the pump rods fitted to post-1920 internal NRV Optimus stoves.

    So a detailed look at both the legs and pump rods seems to further validate the 'gut instinct' attribution of a production date of c.1917/8; so could it be the case that Optimus did continue to fit plain-cut legs to their 'budget' 'S' and 'J' variants of the No.1 stove right up to the end of Optimus external-NRV production, despite the lack of catalogue evidence?
     
  4. igh371

    igh371 SotM Winner Subscriber

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  5. igh371

    igh371 SotM Winner Subscriber

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    Well now I can answer that question that I was asking myself 2 years ago. And the answer is no Optimus didn't keep fitting plain-cut legs to the budget version of their external-NRV No.1 stove beyond 1914/15 - and the proof is here, an external-NRV Optimus 1S which does have legs with feet. Overall this new discovery would seem to support the original contention that this stove must most likely date from the 1912-4 period.
     
    Last edited: Dec 17, 2019