I finally found a semi regular use for my Primus 210 I had for many years. But i wanted to give it a proper all out clean. Including the NRV. I ordered a gasket set from the fettlebox and found a local who sold some extraction tools. The tools arrived and I gave it a try. It slipped and now the corners of the valve are rounded over. So the NRV is stuck... Let's hope it still work and never needs maintenance i guess Goddamit! (sorry for the random rant but I had to vent somewhere)
Yes those NRV's can be a b!tch to remove. If all else fails, you can always desolder the pump tube and access the NRV that way. I had to do that once: Fettling a burmos 21
What tool did you use? There are many recommendations on this forum, how to remove the NRV without damage.
That would have been a good tool when the stove was new, or had a recently replaced nrv. The nrv gets stuck after decades. They round the nrv in my experience. Long soaks of penetrating oil. Weeks even.
Well i know that now. Also this tool is the most common you find if you google for it. no one seems to sell a different one. Anyways I desoldered and can acces it this way
I agree, they are the most common. But, the problem with them has prompted others to make better ones. There are several designs. The key is to keep the "well fitting" wrench ON the nrv, and not have it lift off. Putting the wrench in a vice, and pushing the stove into the wrench is the most common 'good' way to do it. But ... care must be taken to not damage the pump tube. Penetrating oil is your best friend, after patience.
Good to know. Now if i decide to remove the nrv in the future after a good soaking is there a seller you would recommend for a better tool?
There was a really good one that a guy .. here ... used to make. @loco7stove made good ones. There are a few people here that made some that 'locked' the shaft down while turning. Homemade though. The stuck nrv is probably one of the jobs that separates the User from the Fettler.
I had a stuck NRV in an Optimus 111 and even after soaking in releasing fluid for days it wouldn't shift. Then I tried tightening it a tiny bit and that released it.
These are the NRV removal tools that I have: The ones on the right are for different brassies/classic NRV's. I think I bought those two here on the forum. The one on the left is for Coleman NRV's. Those can be had on E-bay The reason I like these because they fit snugly in a pumpshaft and won't wiggle around. Which has less chance of rounding/destroying the NRV.
Thank-you very much for sharing and give your impression, for long time I wanted to know if they were good or not. Super
This is my nrv removal tool, made on a lathe, I was not happy with the chinese i bought on internet. I think the next one will be heat treated
With saw&file or grinder NRV tool can be made from 1/2" socket extension (https://classiccampstoves.com/threads/stovies-workshops-fettling-benches.17229/page-7#post-455796): That needs to be pushed down when opening NRV. Impact bolt gun (with very low torque) can be used for stubborn NRVs' since other end has 1/2" female socket.
Thanks guys for the replies. I can mill the “through” slot as shown on the left in the attached photo. kok seems to have produced the aperture as in the tool (purchased) on the right in the attached photo. The only way I know of doing that is either by broaching or spark erosion? The only other option is to mill the through slot and fit a suitably sized interference fit sleeve, which would mean removing metal from the main shaft...
You could saw it and file to a snug/interference fit. That's worked for mine the last 10 years. Alec.
