After losing a battle with the pump non-return valve on a Radius 119, and confronted with a recalcitrant NRV on a Primus 1025, I did what I should have done years ago: I made a proper tool. Not with a whole machine shop full of equipment, but with just a Dremel tool and diamond-coated cutting disc. It was surprisingly easy to do, starting with a 120mm long high-tensile metric fine steel bolt and a nut. My thanks to Christer and the fine folks over at CCS for showing how such a tool should work. I think there are much more professionally made versions of the tool available there. The principle is that the slotted head of the tool is kept in contact with the head of the NRV by way of a nut kept in place with a modified pump cap. That means that the slotted head cannot slip or ride up and round the head of the NRV. It took a while to cut the slot, trim down the nut etc, but I consider it an hour well spent and many hours and much frustration saved.
I had a similar idea some time ago because Hasag valves have very thin screw slots so that most of the available screwdrivers and tools will not fit. I just used a similar bolt and fitted a piece of a sawblade to get in contact with the slot of the valve head. My tool just misses the modified pump cap which holds it in the center and prevents it from riding up once force is applied. But it already served me well removing stuck valves.
That is a very good idea, Martin. On the Primus tool, the rounded nut is adjusted level with the edge of the pump tube and when the pump cap is screwed down onto it the tool slot is held down against the valve head.
Hi, recently got an “authentic” primus 210. Not my first primus, knowing the drill to check/replace seals and pump leather etc to get it working. Only had lipstick based burner type until now. Disassembled, cleaned and started replacing hardened seals, and check pump leather and nrv. But having the rather soft nrv removal tool/key it had slipped and damaged previously (yes brass damaging iron/steel key). I could not get the nrv valve out and deformed the top of nrv due slipping. Time for new key or approach, not preferring to desolder the pump tube and drill nrv out. I read above nice examples and ideas but they need to sacrifice a pump “cap” to keep key in place, or extra complexity. (And re-use or consume a pump cap) I thought to use somehow a (small) impact wrench, avoid the need to have a lot of (static) force down. I ended up getting a 140mm long hardened hex of 12mm with a 1/2inch socket attached. Use my small lathe tungsten carbide drill/mills to first center de hex key in the lathe, drill a 5mm hole exactly in the middle. Then a 5mm mill centered in lathe, and from center hole slowly cut out a slot wide and deep enough to allow some play to have some room to allow the (previously) deformed nrv cap to go in completely. Intentionally didn’t round the inner slit/slot edges to minimize the risk of be-ing pushed up/out when in use, and grab the nrv head as low (close to base) as possible. Once done, proud on myself i processed real hard&tough toolsteel and created nice quality nrv removal tool (with small issue due mistake). But does it work? Fitted the tool into the pump tube, rotated until i felt it slipping(dropping) down onto the nrv cap the last additional 5/6 mm. Held the 210 body on my lap, and used a hitachi wr14ve, a light 1/2 impact drill with adjustable power and variabele rpm. Started on lowest power setting, added bit down pressure, but no go after few short tries. Moved up to 2nd power setting, kept some down pressure, and then after a few short bursts the nrv came out. All without the need to strongly clamp the 210 body. Notice the deformed nrv head and oval hole on photo which shows the amount of force required to get it out. Also notice the new deformation showing equal from bottom, opposed only on top previous slipped nrv key. It had no (lead) seal in it, i read possible the hardest case to get the nrv out. Afraid perhaps i made it leak or have the 210 body destroyed performed a dry air leak test after inserting good nrv and hdpe seal. Dunked the 210 body pressurized in water for leak test, all was fine. Using a 12mm hex really closely fits a 14mm tube, i was afraid of possible damaging the tube wall when the key/slot wasn’t _exactly_ in the middle, then having an impact hamer demolishing the tube. I spend serious efforts to exactly center the hole/slit (on mini lathe) If you want to repeat the idea and want to avoid/lower that risk maybe use a 10mm hex and 1mm silicone thick sheet as tube (heat oven mat) to protect the inner tube edge. But you will have less meat/room to make the slot. It was not that much of work to create once all set, but need a lathe or mill and tungsten carbide drill/endmill and time to center precisely. Didn’t want to go the route of annealing and re-hardening. Just don’t have a safe room/space for that. I can not say it’s the most easy way, nor the cheapest. The 12mm hex /140mm 1/2inch socket was 17 euro’s then several tungsten carbide mill’s. But it was fun, resulting in a nice quality specialty tool which works, and fun to learn machining hard/touch toolsteel.
