Hi the spirit cup on my Optimus 8 is loose, I have tried reseating it on the tapered nut but it comes loose again after 1st use. Is there a trick that keeps it seated, or does the cup need replacing, any tips appreciated Charlie
Hi Snwcmpr, the threads are all okay and there are no cracks in the cup. The cup will not remain seated on the tapered nut, I have tried tapping it further down the nut with a socket to reseat it. Which I thought had worked until it was used but following heating it was loose again see photos.
I'll take it off your hands while you look for one without a wobbly cup. I have a couple of different stoves with spinning cups including the lovely Svea from @Harder D. Soerensen, all gas tight so I'm not worried, they still prime and work. Harder, a new nipple improved the burn pattern, but not completely happy that the outer cap should glow like it does on higher pressures.
Hi @chas brookes , I measure a spirit cup for an Op.8 at approx 30mm OD with a centre hole diameter of approx 10mm. If you need a replacment Base Camp has them listed: 296c Spirit cup for 8 not 8R £4.50 Best Regards, Kerophile.
Sorry Simes it is a keeper even with a wobbily cup and it roars really well Thanks for measurement details Kerophile it matches, I think it is just suffering from age. I may well get a spare from base-camp
That's OK Chas, wobbly priming cups can put some people of stoves. And there are welcoming homes if that is the case.
Why not try to make some kind of washer that you can put between the nut and the spirit cup? That would make it sit better I will think. Michael
Hi Michael a nut above the cup may well work, can not use one below as the tapered nut goes into the bottom of the spirit cup on the Optimus 8 unlike the 8R
It was not exactly a nut I was thinking about. I was thinking if you have the tools to make some kind of washer out of a tin sheet of aluminum, brass or similar to use as a shims between the nut and the spirit cup. Michael
Sorry Michael I did understand what you meant, must remember to read posts properly before posting it should have read washer rather than nut
Hi Snwcmpr yes that is all the way up, it does in fact stay flat I tilted it to show it was loose. I will probably try a brass cup washer above it to keep it level
I have too many errands today. I will try to take a look at my 8, the same model. It appears to be an 8 just before the 8R.
i think over the years the spirit cup has expanded and contracted so many times it has now got just a little bit bigger than the tapered nut, and is no longer clamped by the nut
Hello Charlie I own a similar Optimus No.8 from the fifties as yours. Mine is only little used and the priming cup sits almost as loose as yours. You may lay a ring of brass or copper wire under or above the cup if this is annoying you. Did you notice I wrote "priming cup" not "spirit cup"? In fact the cup is too small for priming with spirits. These cups are sized for priming the "Russian way". Have a look at this post and my solution for better priming. https://classiccampstoves.com/threads/need-help-russian-8r-clone.34568/#post-354966 Maybe you may want to improve your regulator key and learn how to prevent carbonised fingers. Look here: https://classiccampstoves.com/threads/8-r-differences.30472/#post-309561 Best regards Radler
Hi Radler thanks for great advice may well try some of the solutions, have also someone sending me some brass cup washers which may well do the job cheers Charlie
