Hi, I picked up this nice Optimus 45 recently. It all seems quite good apart from a missing reserve tank cap (I'm waiting for one in the post). I've looked at this thread https://classiccampstoves.com/threads/optimus-45-pre-1962.19299/ to help me date the stove - it has the air release screw on top of the fuel filler cap placing it somewhere in the 1960's. I noticed though that this filler cap has straight, vertical knurling for the 'grip' rather than diamond, cross-hatch knurling. Does anyone know when this style of knurling was introduced? Thanks Trevor
Hi Trevor, what a nice stove you have acquired! Have a look at this post: https://classiccampstoves.com/threads/dating-clues-for-optimus-no-45-and-48-stoves.28117/ And look at the Optimus 45 and Optimus 48 stoves in the Reference gallery to see which one most resembles your one. Please provide us with some more photographs, and tell us what marking is on the base of the tank. Is this an Optimus branded stove, or simply marked "Made in Sweden" Your stove appears to have the sunken filler feature, which indicates post 1957/8 when this feature was introduced to Op. 45 and 48 stoves. The Primus Trading Co was formed in 1962, when Optimus acquired the rights for marketing the liquid fuel Primus stoves. The product lines of both companies were rationalised, although both brands were retained as Worldwide they had loyal dealerships and customers. It seems likely that parts bins were shared between Primus and Optimus manufactured stoves during the transition period, particularly where the part was un-branded. Look forward to seeing more photos of your particular stove, Best Regards, Kerophile.
Hi, I knew I had seen vertical knurling on an Optimus stove before even if it was not an Optimus No.45. Have a look at the filler cap/ air release on a contemporary Optimus No.00: https://classiccampstoves.com/threads/optimus-no-00-post-1962.16252/ Best Regards, Kerophile.
On a closer look, the flame spreader has sweden/sweden and the burner, optimus/primus. What's odd is that there is no stamping underneath the reserve tank. The pump has no leather and is the more recent 'O' ring type. I've had a good look through the gallery and there's nothing quite the same. Photos to follow soon. Regards Trevor
Hi Trevor. Have a read of this thread: https://classiccampstoves.com/threa...s-primus-trading-ab-c-1964.35357/#post-364070 I reckon you have an Optimus No.45 from the transition phase of the Primus trading Co. in the early 1960s. Yours seems to be a "Bitsa" stove, made up from the parts bins of the two companies as well as newly produced parts with the dual, Optimus/ Primus stamping. Best Regards, Kerophile.
Hi Kerophile, Thanks. It's quite interesting and intriguing how the merging of companies resulted in stoves like this. I've now got a replacement reserve tank cap and a new jet. The reserve cap makes it a lot less painful! when pumping the stove. The thread on the pump handle was quite rough. The jet corrects a bit of a wonky flame. I have a filler cap for a SVEA 123 midi/mini pump that was purchased in the mid 1980's - but could have been manufactured quite a while before then that also has the straight knurling. Here's some more pictures of the 'Bitsa' in use. Thanks Trevor
