It's either not hardened correctly or as Christer has suggested, it's been over tempered and therefore annealed (though there is considerable temperature difference between the two). It's a tricky ole business this hardening millarky , it's the tempering that's more tricky than the hardening too Probably hasn't helped by not fully inserting the Penta drive up to the stop (the bigger diameter). Interesting pics Doc, thanks for posting Cheers
Hey, Ben and Longilily, Thanks, to you both. Ben, I didn't crank THAT hard!! Just applied what seemed to be the necessary pressure. Longilily, you are far more educated in this stuff, than me, as I know very little about it. In truth, this happened so long ago, that I can't recall exactly, but I usually fully seat any tool I use. On a similar front, I do recall back when we got into Living History, we had some problems with poorly tempered stuff. A local blacksmith made me a copy of a belt axe from 1750, and also a folding lead ladle for casting round ball. Both items were very poorly tempered, with the axe bit being chewed up by chopping on a dead and fallen pine tree, and the ladle bent in half the first time I used it!! On the other side of the coin, the small knife I bought from him, looked wonderful, but was so hard that it could not be sharpened! Every one in our group tried their hands at it, but to this day, it remains incapable of taking an edge at all. I suspect that, if I threw it down on some concrete, it very well would shatter!! Many years later, and same artisan got MUCH better at his craft, and the later stuff he made was truly excellent in all respects, and is still providing perfect service to this day! Take care and God Bless! Every Good Wish, Doc
Hi, In this situation you have at least three possible outcomes: 1. The screw releases, 2. The brass screw deforms or ruptures, or 3. The steel key deforms or breaks. Something has to give! I guess the user of the tool wants to apply sufficient load that the SRV scew releases and comes free. However, we do know that thread-lock compounds were used it these SRV assemblies to prevent dismantling. If you read the instructions on thread locking compounds such as Locktite Blue, they tell you that the assembly has to be heated to around 250 deg C to degrade the cured locking compound BEFORE attempting removal of the screw to which it has been applied. Getting a longer lever, or a harder steel tool is not the way forward. Heat up the SRV with a torch to persuade the locking compound to release its hold, then insert the tool and un-screw the cap. Best Regards, Kerophile.
Hi, George, I'm aware of applying heat to the stuff with locking compound on it. However, back when I worked in the video game industry (15 years at that job), we used the blue Loc-tite when we wanted to be able to remove parts, without heating them. Never had a problem. When we wanted to parts to be semi-permanent, we used the red Loc-tite, knowing that we would have to apply heat to disassemble those parts. I've never seen an SRV screw with red locking compound on it, except, possibly, this one. Had I known it was there, I would have certainly heated the cap before attempting the job of servicing the SRV. Just never had to do it that way, before, so it never crossed my mind in this instance. Thank you for the excellent information. Take care, and God Bless! Every Good Wish, Mark
Doc, Istr that, apart from ordinary blue and semi-permanent red, there's also a hemlock green thread-lock liquid. Truly poisonous stuff... I once fitted such (in my young innocent [= ignorant amateur!] hobby car days) to a front wheel suspension bolt of a Spitfire - it NEVER budged after that. Not even the oxyacetylene torch freed it. I sold the car a decade or so later, bolt still sat like welded in place...
On that very note, I machined a 3mm hex-key for a Brand new Katadyn cap Ross sent me a few days ago, and got to carried away and rounded off the hex drive in the screw !! The key (or rather the flats/corners of the key were still in good shape), that particular Hex-key was machined out of Stainless Steel. Cheers
Hi Doc, no worries! I just checked the instructions, and they are not for a Locktite product. The thread locker Blue that I was referring to is made by V-tech, and is referred to as "medium strength" nevertheless, the instructions are: "For disassembly, apply localised heat to the nut or bolt to apprx. 250 deg. C. and disassemble while hot." I remember Doug Weise referring to the locking compound used on Svea 123 and similar SRVs and pointing out the need to decompose this material before attempting to unscrew the cap. Best Regards, George.
Hi, here is a link to a post where Doug Weise mentioned the treadlock on Svea 123 SRVs: https://classiccampstoves.com/threads/svea-123-research-project-prelim.11516/ Best Regards, Kerophile.
Having to get out of this, I used one of the Penta-keys (that's nicely over sized in comparison to a 3mm hex key) to 'Broach' myself a new drive (by carefully placing the Penta-key over the hex-drive screw and carefully tapping the key downwards and in effect, cutting itself a new drive), albeit now it's a Penta drive instead of a hex drive, applied some heat whilst adding some leverage to the key, and voila ! I did find that the thread lock dried pretty quick when the heat was taken away, so I think keeping the screw continuously heated whilst undoing is the way to go. A Katadyn hex screw broached to a Penta screw ..... At least it means the whole cap is serviceable now Cheers
If one applies heat to remove the pentagonal screw, the pip, and possibly the filler cap gasket, will be destroyed, by the heat, and will require changing. If one tries to remove the pentagonal screw without heat, there is the risk of damaging the pentagonal screws 5 sided hole. I think Docs tool twisting is a fluke, and not a common occurrence. Caution and care should be the order of the day when servicing one of these caps. Knowing Doug and his in depth work he does, if he needed research data returned to him I can safely assume that working on these is not as simple a matter as unscrewing a lightbulb to replace a light. There will be a few, or more, damaged caps as a result of less than capable users. But without servicing these caps, there will be an SRV that is not functional. (Well there probably are already a lot of those) I see these discussions as a great service to the stove community. Ken in NC
My question is what pressure is the Srv supposed to open at? A small threaded tube that accommodates the cap threads could be made to test and exercise the Srv opening point pressure. or test if it fails it's rated opening. I like the idea of a test tool to avoid excess pressure testing of a fuel tank.
Gary had sent me an email a few years ago on how many turns required to get a set pressure. Unfortunately, my home puters hard drive went south a few years ago and I lost the info. He has data stored, just hard to relocate. All of us are getting old. Duane
Morning, Shagratork, As you will see, this video notes the following: "Playback on other websites has been disabled by the video". So, you'll have to watch this on YouTube. No big deal, actually, just FYI, if you didn't already know. Take care, and God Bless! Every Good Wish, Doc
Looks like Gary's disabled you Trevor. Maybe just post a link to the YouTube video. Alternatively, after pressing the play button on Trevor's post you can click on the "Watch this video on YouTube" link on the disabled page. Ben
Hi Doc Yes I did know, but all one has to do is click on the Youtube icon and you are taken straight to Youtube where the video plays automatically. I actually did not want the video to show on CCS, but the new software automatically inserted the video. So, not a real problem and a very good video on servicing an SRV. Regards,
Hi Ben Gary posted many videos on CCS in the past. They are all disabled for direct links in all non-BernieDawg websites. I knew this when posting the link. Edit: I would be quite flattered if BernieDawg had disabled videos because of me, but I have to say that all his videos were disabled quite a long time ago.
