MarkC Posted November 15, 2009 Share Posted November 15, 2009 Having used 3-links/screw couplings in 4mm scale for over 30 years, it's time to admit that Anno Domini has caught up with the eyes. Problem is, what to replace them with? I'm minded towards Jacksons, having been involved with a group that used them in the mid-70s, but I wondered what others think. To me they're the most inobtrusive of all autocoupling systems, and cheap too! Over to you guys! Link to post Share on other sites More sharing options...
Coombe Barton Posted November 15, 2009 Share Posted November 15, 2009 Unobtrusive, of course. It's what I'm using. But despite being a bit of bent wire they really should be thought of as precision engineering. Gauges and checking and protection of the coupling when handling stock off track are all required. I appreciate that you know that, just wanted to post before anyone gets discouraged by thinking that it's just a bit of bent wire. However the coupling is only part of the system. The electromagnet, its construction and positioning, is just as important. I've recently succeeded in making some that are so strong that they glue the wagon to the track as it passes over and uncouples, with a resulting pile up. The distance from the end of the magnet to the uncoupling armature is also quite critical. Very few articles I've seen address the system nature of any auto couplings, the operation as well as the mounting. The original AJ articles in MRN in the '60s did, as does the MRJ article reproduced in the Scalefour Society book (the diagrams in those look like the originals), so if anyone is thinking of using the AJ ystem then that book is definiitely the one to get. However Chris Pendleton's review of this in MRJ 194 does highlights what I've been finding, the lack of suitable magnetic activation devices. My experiments to date, using iron nails and various windings. I wish I could find some of the original stuff I had (last seen more than 20 years ago) about the recommendations by the original team of winding your own solenoids, but it seems to have disappeared. In fact the only coupling type that does not require engineering at track level is the three link withe the heavnly hand.. Link to post Share on other sites More sharing options...
craigwelsh Posted November 15, 2009 Share Posted November 15, 2009 The book mentioned can be purchased online from the Scalefour Society along with some new jigs that if correctly assembled and used produce consistently accurate hooks http://www.scalefour.org/e-shop/publications.htm. The etched bending jigs were produced in the Manchester group and the instructions and more details on them are available from http://www.palatinemodels.co.uk/ where you can also buy them. Tony Williams was demoing at Scaleforum using one of my wagon chassis fitted with the new hinged AJ plates and 1.2mm iron wire droppers. The electromagnets he used were from MSE I believe and I also have some of these but haven't yet used the hinged couplings with them. The instructions for the electromagnets mention 9-12V supply but no mention of the current so I need to check exactly what Tony has along with the depth of the dropper. i've not managed to get the flexible system of AJ to more than wobble in my attempts so far but the tail may have been too short. I think i'll use the hinged one instead now though. I'd therefore agree with John's comments that you want constant hooks (use the jigs i'd recommend) and that electromagnet placement and dropper height are the key to success. The hinged version also allows more flexibility in aligning the coupling but can get difficult with vacuum cylinders etc. Link to post Share on other sites More sharing options...
bertiedog Posted November 15, 2009 Share Posted November 15, 2009 With the electromagnets. it's best to make a decision to make a standard type on a standard core, and then adjust the voltage to give the right pull. A small wall wart power pack can supply the power needed and they are adjustable. I use a coil on a 1/4 ferrite rod, ( 3/16 steel will do), with 300 turns of 32 swg copper enamelled wire. This works with the end of the ferrite at track surface, with about 7 volts DC to give the right field. This works with both AJ types, there are differences with use of iron wire over steel guitar, but the differences are minimal. Always make all the bends on a jig, even slightly wrong will be OK, as long as it is used for all stock. For club use be more careful, and get the jig right, or buy in a commercial one for group use. They are cheap to make and about the best design for the UK, unless modern image when Kadee are even better, but you have to justify using knuckle couplings. They are inconspicuous enough for vintage Victorian stock, I would recomend using gun black on the steel wires, and never attempt to paint them black near the head. Stephen Link to post Share on other sites More sharing options...
Coombe Barton Posted November 15, 2009 Share Posted November 15, 2009 i've not managed to get the flexible system of AJ to more than wobble in my attempts so far but the tail may have been too short. I think i'll use the hinged one instead now though I'll have to try the hinged ones. I've been using the sprung type thus far, hence the gluing of the wagon to the track. Mag strength would be very much reduced, which is a benefit as then small commedcial relays could be used.may buy a http://www.maplin.co...&C=SO&U=Strat15 to try. From memory it was recommended that magnet positions were indicated by a lineside feature, maybe a clump of grass, a fencepost, whatever is convenient. Does anyone else think that ome work needs to b published on the operational side of the AJ coupling, the magnets, the positioning the control (including arc supression) so that it becomes a 'system'? Link to post Share on other sites More sharing options...
MarkC Posted November 15, 2009 Author Share Posted November 15, 2009 Many thanks for the replies, chaps. Appreciated. Yes, the electromagnets are 'interesting', aren't they? Regarding the jigs, I bought some several years ago, but never 'got round' to the switchover before. Anyway, thanks again. I'll perhaps put some pics up once I get started on it all. Mark Link to post Share on other sites More sharing options...
10800 Posted November 16, 2009 Share Posted November 16, 2009 For magnets I've quite happily used Seep electromagnets with the top of the magnet about 1-2mm below sleeper level. Easy to adjust up or down if you need more or less pull. Link to post Share on other sites More sharing options...
craigwelsh Posted November 16, 2009 Share Posted November 16, 2009 Many thanks for the replies, chaps. Appreciated. Yes, the electromagnets are 'interesting', aren't they? Regarding the jigs, I bought some several years ago, but never 'got round' to the switchover before. Mark Unless you made your own you wouldn't have been able to buy the main hook bending jig before Scaleforum last year http://www.checksystems.com/palatinemodels/AJBendingJig.html . There does need to be a proper article on the system as Chris Pendlenton's book review sort of tried to review the etched jigs as well which were designed after the book was in print. He also didn't consult with the jig designers so some of his points may have been corrected. Rod what power supply have you used on your Seep magnets? Link to post Share on other sites More sharing options...
10800 Posted November 16, 2009 Share Posted November 16, 2009 Rod what power supply have you used on your Seep magnets? Hi Craig Just a Seep EM-1 and a p-t-m switch with 16V AC straight off an auxiliary transformer. Apparently these are designed for N-gauge uncoupling. Link to post Share on other sites More sharing options...
Sir Balin Posted November 16, 2009 Share Posted November 16, 2009 Bertiedog, you mention a 'small wall wart power pack'. Could you expand on this? I'm not sure if it was just a typo, and you were referring to something from WalMart, or something else entirely Ian Link to post Share on other sites More sharing options...
bertiedog Posted November 16, 2009 Share Posted November 16, 2009 Bertiedog, you mention a 'small wall wart power pack'. Could you expand on this? I'm not sure if it was just a typo, and you were referring to something from WalMart, or something else entirely Ian I deeply apologise for the Americanism slipping into an Imperial posting, a "wall wart" refers in a derogatory way to the black boxes that plug into the main socket , and have a lead from them with a low safe voltage for the equipment, a new name for a switched mode mains power pack, and nothing to do with Wall Mart. They come in lots of Flavours, fixed outputs, universal units, or computer power supply's, it is just the generic name for a modern power supply. Stephen. Link to post Share on other sites More sharing options...
Penlan Posted November 16, 2009 Share Posted November 16, 2009 If you go to http://www.mmrs.org.uk/technical/ajcoupling.htm it's all there. But then that might reduce a few book sales. Penlan Link to post Share on other sites More sharing options...
Wizard of the Moor Posted November 16, 2009 Share Posted November 16, 2009 I am using the Model Signal Engineering electromagnets as Jackson uncouplers on my layout, but I found that a small 'wall wart' type power supply wasn't powerful enough to drive the coils without them buzzing. Moving to a heftier supply capable of delivering up to 1.2 Amps solved the problem, and now the coils work without problems. Another thing to consider is using a relay to switch the coils on and off. This reduces the risks of the high current drawn by the coils burning out the contacts of the little push-to-make switches that are typically used on control panels to activate the uncoupler magnets. Cheers, James Edit: I actually use a 1200mA supply for the MSE coils. It's available from Squires (Item RPS12V) or Maplins. No connection to either supplier etc. etc. J. Link to post Share on other sites More sharing options...
bertiedog Posted November 16, 2009 Share Posted November 16, 2009 I am using the Model Signal Engineering electromagnets as Jackson uncouplers on my layout, but I found that a small 'wall wart' type power supply wasn't powerful enough to drive the coils without them buzzing. Moving to a heftier supply capable of delivering up to 2 Amps solved the problem, and now the coils work without problems. Another thing to consider is using a relay to switch the coils on and off. This reduces the risks of the high current drawn by the coils burning out the contacts of the little push-to-make switches that are typically used on control panels to activate the uncoupler magnets. Cheers, James As always it depends on the coil details, my 300/400 turn ones draw about .65 amp at 8 volts. The last ones were done with 32 swg wire on ferrite cores, but steel nails works as well. I tend to use scrapped wire from trashed TV's etc, recovered from screen coils and transformers, have a hunt for a broken free binned TV set from a skip!!(or a scrapped computer CRT monitor!) It will provide all the wire you need for several coils, (and the ferrite cores if you are lucky). The problem with the switches on all coils is not the contact when pressed, but the release, when all the stored electromagnetic energy is released in a collapse, and causes a spike of voltage that will jump the contacts and cause burning. But this is easy to suppress, a capacitor of about 1 to 10 uf across the contacts will suppress the spike. Use a non polarised one, or be careful which way round they are wired in. I am assuming use of DC here, rather then AC like a point motor coil. The AJ method was to use Post Office relay coils, these are very difficult to source now, and modern relays are totally different, much smaller in size. Just modifying a modern relay is difficult as the arm has to be removed to open the magnetic pole to allow it to work the uncoupler, and most modern relays do not like being taken apart, being cased and made of plastic, which can break up on opening up the sealed cases. But coils are not difficult to wind, you can buy fine enamelled copper wire on the net, {or use the scrap tv type}, and big diameter long nails provide good cores. Take a 5 to 6mm diameter nail stem and slip on a 1/2 inch washer under the head, add another washer at the other end, temporarily held with tape or a dab of epoxy, and then fill the gap with wire, about 500 to 600 turns. The washers can be made from plasticard or scrap card. The whole coil can be bound in tape to protect it. The nail head is the upper magnetic pole, and will be at the level of the sleeper surface, cover it with false box etc., or get it just below ballast to hide. Bore a hole through the board from underneath with a spade blade in a hand drill, and then glue the coil into the hole and wire up. This will vary with your baseboard type. Stand two wagons in known working order and adjustment on the track , and power up with a universal 1.5/2 amp wall wart power supply or an old DC controller, ( it can power all the un-couplers, there is no need for one each). Then simply wind up the power from about 2 volts in the steps provided till the couplings react and operate properly. If your are lucky, it will work first time at about 6 to 8 volts. If unlucky, it may be unable to work even at twelve, and you might have to re-wind the coils, perhaps a shorted turn has occurred. But the usual problem is the magnet is too powerful and all you have to do is lower the voltage, and the most adjustable system is to use a devoted old H/M controller, or equivalent, to give infinite adjustment to give a perfect pull, without attracting the axles etc. I have several of these old units about, used for aux power, 16 vac and variable 0 to 12 vdc , some plugged in, and all with spare leads fitted, to allow them to be used for all purposes as well as running lights and coils. Hope this all helps, the AJ couplings really work well, there modern alternatives as well, but the AJ is so easy to make and cost is so low it is the most attractive one. Hope this all helps. Stephen. Link to post Share on other sites More sharing options...
Sir Balin Posted November 17, 2009 Share Posted November 17, 2009 Thanks for that Stephen - my knowledge of Americanisms obviously has room for improvement. I'll try to keep up in future! Ian Link to post Share on other sites More sharing options...
MarkC Posted November 18, 2009 Author Share Posted November 18, 2009 Unless you made your own you wouldn't have been able to buy the main hook bending jig before Scaleforum last year http://www.checksystems.com/palatinemodels/AJBendingJig.html . Well, these jigs date back to 1998 or before - I bought them before my last house move & have only recently found the Jiffy bag containing the kit of wire, jig, centre/height gauge & 'destructions' . They came from 'Martin's Model Accessories' - Martin Brent Link to post Share on other sites More sharing options...
10800 Posted November 18, 2009 Share Posted November 18, 2009 Well, these jigs date back to 1998 or before - I bought them before my last house move & have only recently found the Jiffy bag containing the kit of wire, jig, centre/height gauge & 'destructions' . They came from 'Martin's Model Accessories' - Martin Brent Yes, even earlier than that I believe - not quite as convenient as the new ones though, but the only commercial jig option for a while. They are mentioned in the MMRS book I think, you do have to be aware of the steel jig which doubles as a height-setting jig in that cradle, which can affect the alignment of the couplings you are adjusting. The first time I ever saw AJs was on Martin's (RIP) wonderful layout 'Hope Mill'. Link to post Share on other sites More sharing options...
MarkC Posted November 18, 2009 Author Share Posted November 18, 2009 Yes, even earlier than that I believe - not quite as convenient as the new ones though, but the only commercial jig option for a while. They are mentioned in the MMRS book I think, you do have to be aware of the steel jig which doubles as a height-setting jig in that cradle, which can affect the alignment of the couplings you are adjusting. The first time I ever saw AJs was on Martin's (RIP) wonderful layout 'Hope Mill'. Just managed to decipher the postmark on the bag - 1997! Thanks again to all for their contributions to the thread so far. I'll be looking at electromagnets in due course - there's plenty of 'food for thought' here now Link to post Share on other sites More sharing options...
Tony W Posted November 18, 2009 Share Posted November 18, 2009 Mark The test track I was using at Scaleforum (mentioned earlier by Craigwelsh) uses two PK Magnets wired in series and connected up to an old Minimodels Smoothflow transformer that puts out 2.5 amps. Please remember that the relationship between the power put through the magnet, the diameter of the dropper, and the length of the dropper are important for effective coupling. When building the test track I didn't use any mathematical formulas to work it out just a bit of trial and error. Do remember that your dropper needs to be of sufficient diameter for the magnet to pull it down. Wire such as paper clips is really only effective if you have a magnet of sufficient strength. Also try and make sure that all your stock has droppers of a similar size otherwise you may end up with inconsistent uncoupling. One final thing you'll find the Palatine jigs a lot easier to use than the Martins Model Accessories ones but I would say that! Regards Tony Link to post Share on other sites More sharing options...
MarkC Posted November 19, 2009 Author Share Posted November 19, 2009 Mark The test track I was using at Scaleforum (mentioned earlier by Craigwelsh) uses two PK Magnets wired in series and connected up to an old Minimodels Smoothflow transformer that puts out 2.5 amps. Please remember that the relationship between the power put through the magnet, the diameter of the dropper, and the length of the dropper are important for effective coupling. When building the test track I didn't use any mathematical formulas to work it out just a bit of trial and error. Do remember that your dropper needs to be of sufficient diameter for the magnet to pull it down. Wire such as paper clips is really only effective if you have a magnet of sufficient strength. Also try and make sure that all your stock has droppers of a similar size otherwise you may end up with inconsistent uncoupling. One final thing you'll find the Palatine jigs a lot easier to use than the Martins Model Accessories ones but I would say that! Regards Tony Hi Tony Thanks for taking the time to post. Some very good issues raised too. All makes sense, particularly standardisation of droppers. I'm away from home at present, but will get stuck into making & fitting couplings as soon as I get back. Cheers Mark Link to post Share on other sites More sharing options...
craigwelsh Posted November 19, 2009 Share Posted November 19, 2009 I am using the Model Signal Engineering electromagnets as Jackson uncouplers on my layout, but I found that a small 'wall wart' type power supply wasn't powerful enough to drive the coils without them buzzing. Moving to a heftier supply capable of delivering up to 2 Amps solved the problem, and now the coils work without problems. Cheers, James Any chance of the make and voltage of that transformer as thats exactly the issue I had and could do with getting something tried and tested. If its something odd i'll try and look for a Maplins equivalent for example. RS Spares has a couple of 2A 9V listed I could get if needed. I understand your point Stephen about winding your own coil to avoid a large amperage but i'd prefer to just get these off the shelf and be consistent with the ones the club uses. Link to post Share on other sites More sharing options...
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