Edit: later identified as a 48. Title amended. I was given my Grandad's Primus stove last week. I started to clean it to discover it is an Optimus 45, made in Sweden. I found this group and this thread while searching for clues to date the stove. I knew from his age and the year my Grandad passed away that the stove could date to before WW2. This is the stove: It has some of the characteristics of your 1930s stove: The top of the tank is engraved only, with "OPTIMUS No. 45" and "MADE IN SWEDEN", in English script. There is no additional logo, nor script on either the top or side of the tank, filler cap, or pump cap. The centre of the base of the tank is marked "A.B.OPTIMUS", "STOCKHOLM" and "MADE IN SWEDEN". The feet are steel. The air release is mounted on top of the filler cap. The filler is mounted flush on the top of the tank. However: The legs are a more relaxed form The pump has a steel shaft but does have a leather pump washer. Could my stove date from the 1930s? Thank you
Hi, your stove could date from the 1930s. If it is marked up as an Optimus No.45 it would have had a roarer burner when it left the Factory. The silent burner “sister” stove was an Optimus No.48. The legs on these collapsible stoves are detachable so it is possible that they were replaced during a long and possibly adventurous lifetime. It is quite in order for these Optimus stoves to have a steel pump rod. The vast majority of stoves of this age will hae used leather pump washers. Best Regards, Kerophile.
Hi @Philip Ward and welcome to the forum. +1 to what Kerophile said. The two big problems with Optimus were their lack of any date coding and the fact that these stoves were all made up of removable and replaceable parts which were often compatible across ages, so an older stove can be fitted with more modern parts and vice versa. We know yours has a replacement burner so it is possible (?likely?) that the spirit cup beneath the burner may also have been swapped. Question 1: Does the spirit cup have a dimple in one part of it? You can make it out in post 2 of this thread in the right hand pictures at about the 5 o'clock position. Question 2: (Harder when there is nothing to compare with) What height is the gap from tabletop level to the lowest part of the underside of the tank? Would it be about 6mm or about 15mm? see the side by side profiles pictured in post 6 of this thread. Both pot bellied and dimpled features would be indicators of an older stove, although the +-dimple on yours is less reliable due to its known change of burner. Hope that helps and looking forward to more discussion. Dean
Hi @Dean thank you for the welcome. My stove is No 48. My mistake, I started cleaning, saw the double underline under the o of No and saw a 4 and assumed it was a 45 as featured in this thread. I think on the whole it is original (neither my father nor grandfather were engineering types) except for the legs, wrong shape, and the top plate which is not branded (easy to replace). to answer your questions: The spirt cup has a significant dimple in it but interestingly it also has what appears to be a flame deflector spot welded above the dimple: 5 * 1mm shims fit between the belly of the tank and my work top. I need to be careful not to hijack this thread but we are potentially discussing a 1930s Optimus so I think I'm fine so far. If I wanted to start a restoration thread where I can ask questions and share progress, which Forum should I post in?
@Philip Ward The priming cup is as it left the factory. It's an early design. The plan is for the last flame of the prime to be able to light the silent burner. Later they just used a cheaper priming cup. Look over the gallery when you can. Moderators- perhaps these posts can have a new thread re 1930s Optimus 48?
@Philip Ward It might be best to start a thread in the Stove Forum. I see that Scrambler has made a similar suggestion to detach it from this Optimus 45 thread as we really are now wandering off topic.
Early Optimus burner? I honestly don't know, I think my dad would have scrapped it but I said I would take it and restore it. I can remember it being used constantly on family camping holidays in the 60S. I also have a soft spot for old technology. I believe I have a 293a and a 205 combination. Admin, sorry if the picture has not embedded, I'm doing my best. It does show on preview.
Hi @Philip Ward From your measurement of 5mm, there can be no doubt that your stove is one of the "pot bellied" models which, I think were in production from somewhere like 1915 to perhaps mid 1930's. These would likely have been designated as 2 pint stoves, where the later (shallow bellied) examples were 1 3/4 pint. There is some interesting info in Ben Hall's post and thread Double Vision. As Kerophile said, the 45s and 48s were sibling stoves just with a different burner, so what applies to the 45's applies to your 48. The reason behind a start point of 1915 is to do with the take over of Lux and the incorporation of some of their design features - notably the priming dimple and 15 degree leg bends (although, as noted, your stoves legs are a later ?35 degree? design). The mid 1930's cut off will relate to the cessation of the pot bellied design and the change of base stamp address from Stockholm to Uppl Vasby. In Double Vision, OMC refers to subtle changes to the base stamping which might be changes over time (if so, I don't think we know when). There are similar dating issues with the Optimus 00, no pot bellies there (that I know of!) but the incorporation of the word Patent in the top stamping along with the change from Stockholm to Uppl Vasby! Two things unresolved - pot legs are a later design. We could dwell on when but more likely, they have been replaced - if not, a later stove in the sequence. Second, your initial picture seems to suggest that the filler spout is sitting in a horizontal depression- see what appear as little splay lines either side of the cap. The indented filler was introduced in c.1958 (by which time pot bellied stoves had definitely ceased) but an earlier suggestion by me was that it was "(re)introduced" then. I don't have the memory to recall where that suggested nugget came from, but if it had been used early on and your stove has an indent, then yours would be earlier, rather than later and could predate 1930's. I have spent far too long looking at this!!
Thanks Christer for relocating this to stove forum discussion. @Philip Ward thanks for posting and welcome, it's all good. Grand dad's Primus.. awesome! all, Dean, c'mon you're just getting started hahaha 2 things are clearly stated in OP (A&B below) (Philip there's no harm in double checking, confirming) A. The filler is mounted flush on the top of the tank. I agree the image surely looks like it could be sunken filler, i thought so too (apparently not) B. base of the tank is marked "A.B.OPTIMUS", "STOCKHOLM" to-date, we have understanding some point mid 30s "Stockholm" was replaced by Upplands Vasby on all brass stove stamping. i agree with what's been said above, given B, that puts age sometime *mid 30s or earlier. credit Bryan *mid 30s is 1933-36 thx
@Philip Ward can you post pictures of the stove now that you've clean it up a bit? @Christer Carlsson title currently says Opimus 80. can you add the missing t if you get the chance? Thanks and regards John
@Jeopardy I'm not sure I would claim to have cleaned the stove. I just rubbed a little more so I could identify it as a No 48. I've manged to take everything apart except for the NRV and the jet, if that is the correct terminology, both of which require dedicated tools. I've had a bore scope in the tank and everything looks good in there. Finally the burner has heavy white deposits in it, I assume lead from leaded petrol? I've been looking for tools and methods to clean the inside of the burner. The stove I think is complete and original except for: Support legs, historic DIY replacements Top plate trivet is an unbranded replacement Tank cap is missing I have no tools I've been shopping around to see what is available; replica and used part supply appears good. The stove:
@Paul Lydon , just got off the phone to my dad. He ran it on leaded petrol. I need to clean the deposits and also the melted lead washer out of it. I already have a supply of paraffin for it.
Hoping with all due respect this is a slight memory lapse- using petrol in a paraffin pressure stove such as this is dangerous to the point of being potentially lethal.
Kerosene only - to attempt to run this on petrol will risk serious conflagration! The German word Petroleum, sometimes appearing on instructions for these kinds of stoves, translates as kerosene. Peter
In Britain, literature for earlier stoves (and other things such as bicycle oil lamps) often used the term 'Petroleum' for paraffin. 'Petroleum spirit' was the common term for petrol. Although this morphed to 'paraffin' and 'petrol' as the common terms after the Edwardian period, even today petrol pumps on garage forecourts and cans used for storing and carrying petrol must, by law, be marked 'Petroleum spirit- highly flammable'.
