david robertson Posted February 8, 2007 Share Posted February 8, 2007 I've clumsily managed to break one of the strap screws on a 30-key Jeffries (trying to straighten it). The box has had threaded inserts fitted, but of a countersunk type I've never seen before. Does anyone out there know where I might be able to find one like it? You can see it here - (I've just tacked the picture onto the end of my French holiday home website). Link to comment Share on other sites More sharing options...
PeterT Posted February 8, 2007 Share Posted February 8, 2007 I've clumsily managed to break one of the strap screws on a 30-key Jeffries (trying to straighten it).The box has had threaded inserts fitted, but of a countersunk type I've never seen before. Does anyone out there know where I might be able to find one like it? You can see it here - (I've just tacked the picture onto the end of my French holiday home website). Hi David, Don't know whether it was this size, or (most likely) a bit larger, but I recall this type of counter-sunk thread on certain cameras, to enable mounting on a non-standard tripod. So a decent shop, selling a wide range of camera assessories, might be a starting point. Regards, Peter. PS - like the website! Link to comment Share on other sites More sharing options...
Theo Posted February 8, 2007 Share Posted February 8, 2007 David Leese sells something similar. Link to comment Share on other sites More sharing options...
david robertson Posted February 8, 2007 Author Share Posted February 8, 2007 David Leese sells something similar. I've already tried David, but unfortunately, he doesn't have countersunk inserts, or any strap screws with such a fine thread. At a pinch, I may try tapping a new thread in the insert, to match a different screw. Link to comment Share on other sites More sharing options...
Pete Dickey Posted February 8, 2007 Share Posted February 8, 2007 To be frank, the insert is of pretty basic design. Any self-respecting engineering workshop or model engineers would be able to knock you something like that out in pretty short order for not a serious amount of loot. If you are struggling then send it to me and I'll get it done for you. Pete Link to comment Share on other sites More sharing options...
d.elliott Posted February 8, 2007 Share Posted February 8, 2007 (edited) You are right Pete, but you will have to provide and fit a new threaded bit for the thumb screw as well. I would also try Marcus as well Dave Edited February 8, 2007 by d.elliott Link to comment Share on other sites More sharing options...
david robertson Posted February 8, 2007 Author Share Posted February 8, 2007 You are right Pete, but you will have to provide and fit a new threaded bit for the thumb screw as well. I would also try Marcus as well Dave Yes, I tried Marcus too, but he hadn't come across a countersunk version either. As for the one-off solution, many thanks for the kind offer, Pete, but I'm doing this one for an impecunious friend, and I don't think he'd thank me for taking that route! Link to comment Share on other sites More sharing options...
Chris Ghent Posted February 9, 2007 Share Posted February 9, 2007 It is possible the maker took an existing screw and drilled and tapped, then shortened it to make the insert. If this is true then making another would be a snip. Work out the size and TPI (threads per inch) of the current one, buy another screw, shorten, drill and get it tapped in the same size as the thumbscrew. Probably need to be a brass screw to make it easy. Chris Link to comment Share on other sites More sharing options...
Henrik Müller Posted February 9, 2007 Share Posted February 9, 2007 ...The box has had threaded inserts fitted, but of a countersunk type I've never seen before. Does anyone out there know where I might be able to find one like it? ... Risking the wrath of the honourable members of c.net, by mentioning the word "Stagi 18-key" in the same sentence as the word "Jeffries" , I can say that I recognise the type from my little Stagi (since I moved them around). Not much help, though, but only proves that it is a modern thing, and therefore should be possible to locate. /Henrik Link to comment Share on other sites More sharing options...
david robertson Posted February 9, 2007 Author Share Posted February 9, 2007 ...The box has had threaded inserts fitted, but of a countersunk type I've never seen before. Does anyone out there know where I might be able to find one like it? ... I can say that I recognise the type from my little Stagi Thanks, Henrik - that's just the sort of lead I was hoping for. Now the hunt begins! Regards, David Link to comment Share on other sites More sharing options...
Paul Woloschuk Posted February 9, 2007 Share Posted February 9, 2007 (edited) Looking at the countersunk screw, it looks very much like those screws that you use to fix bathroom mirrors to a wall (you know the ones - they have a chrome domed screw-in cover) - maybe someone's ground-down the domed cover and made their own strap screw out of it. It might be worth checking out a local hardware / DIY store - just a thought . Edited February 9, 2007 by wolosp Link to comment Share on other sites More sharing options...
Pete Dickey Posted February 13, 2007 Share Posted February 13, 2007 You are right Pete, but you will have to provide and fit a new threaded bit for the thumb screw as well. I would also try Marcus as well Dave Interestingly Dave when I made a couple of threaded inserts for my Jeffries I found that the threads on the thumbscrews were standard BA size. Pete Link to comment Share on other sites More sharing options...
david robertson Posted February 15, 2007 Author Share Posted February 15, 2007 You are right Pete, but you will have to provide and fit a new threaded bit for the thumb screw as well. I would also try Marcus as well Dave Interestingly Dave when I made a couple of threaded inserts for my Jeffries I found that the threads on the thumbscrews were standard BA size. Pete The one I broke also had a BA thread (2.2mm diameter, I think). I believe the British Association introduced BA threads in the 1890's - maybe Jeffries were "early adopters"? Anyway, thanks to everyone for your helpful ideas - I have now removed the picture from the website. David Link to comment Share on other sites More sharing options...
Dave Prebble Posted February 15, 2007 Share Posted February 15, 2007 The one I broke also had a BA thread (2.2mm diameter, I think). I believe the British Association introduced BA threads in the 1890's - maybe Jeffries were "early adopters"? Anyway, thanks to everyone for your helpful ideas - I have now removed the picture from the website. David not really an answer to your question David but ..... I have seen a few earlier Jeffries with no captive nut at all so its also quite possible that a BA insert could be a retrofit. An interesting variation I have come across a number of times is a similar to the 'Helicoil' repair system used in engineering. I presume the following was used as an upgrade or repair rather than when the instrument was made. Hard brass wire with a diameter that will sit well into the 'V' groove of the bolt thread was wrapped tightly around to form a coil using the actual screw as a former and, in some cases, tinned with solder. A hole would then be reamed out in the woodwork (possibly tapped for added purchase) and the coil sinply glued into the hole and filed flush. I have not tried this dodge for myself as it just seems easier to fit proper nutplates, but those coil inserts I have seen, appear to have stood the test of time pretty well. Regards Dave Link to comment Share on other sites More sharing options...
d.elliott Posted February 15, 2007 Share Posted February 15, 2007 (edited) The one I broke also had a BA thread (2.2mm diameter, I think). I believe the British Association introduced BA threads in the 1890's - maybe Jeffries were "early adopters"? Anyway, thanks to everyone for your helpful ideas - I have now removed the picture from the website. David not really an answer to your question David but ..... I have seen a few earlier Jeffries with no captive nut at all so its also quite possible that a BA insert could be a retrofit. An interesting variation I have come across a number of times is a similar to the 'Helicoil' repair system used in engineering. I presume the following was used as an upgrade or repair rather than when the instrument was made. Hard brass wire with a diameter that will sit well into the 'V' groove of the bolt thread was wrapped tightly around to form a coil using the actual screw as a former and, in some cases, tinned with solder. A hole would then be reamed out in the woodwork (possibly tapped for added purchase) and the coil sinply glued into the hole and filed flush. I have not tried this dodge for myself as it just seems easier to fit proper nutplates, but those coil inserts I have seen, appear to have stood the test of time pretty well. Regards Dave a helicoil needs a good substrate to lock back into, so as to create a female thread. I may have missed something along the line-- but I understood that part of the problem was that David broke a thumbscrew, not just the insert. Is this true? Are we answering the right question? Dave E Edited February 15, 2007 by d.elliott Link to comment Share on other sites More sharing options...
Dave Prebble Posted February 15, 2007 Share Posted February 15, 2007 a helicoil needs a good substrate to lock back into, so as to create a female thread. I may have missed something along the line-- but I understood that part of the problem was that David broke a thumbscrew, not just the insert. Is this true? Are we answering the right question? Dave E Hi Dave, As I said "not really an answer to your question David but ....." I was pointing out that some early Jeffries Screws went straight into the wood and noting a dodge that has plainly worked for others in the past; also that the existing insert is quite likely to be a retro-fit. It seems to me that we have now established that the thread is standard BA so Chris Ghent's solution would appear to be simple enough to carry out. Might need a bit of jiggery pokery to remove any broken section from within the insert but that should not be too difficult. Regards Dave P Link to comment Share on other sites More sharing options...
Chris Ghent Posted February 16, 2007 Share Posted February 16, 2007 8BA has a major diameter of 2.2mm Chris Link to comment Share on other sites More sharing options...
david robertson Posted February 16, 2007 Author Share Posted February 16, 2007 I may have missed something along the line-- but I understood that part of the problem was that David broke a thumbscrew, not just the insert. Is this true? Are we answering the right question? Dave E Well spotted, Dave! The insert is fine - and there's nothing stuck in it. If I could find a thumbscrew with a BA thread I'd be happy as a pig in the proverbial. Failing that, a countersunk insert and matching screw with any kind of thread... David Link to comment Share on other sites More sharing options...
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