I’m looking for info on making your own magnetic uncouplers.
wschart - Welcome to trains.com! [C):-)]
Are you thinking of permanent magnets or electromagnets?
Welcome to the forums
There have been several posts on using the little round rare earth magnets. If you go to “Search our Community,” downthe right hand column a little way, you may find some matches…
Good luck,
Richard
I’m curious about such a project, too. But search here wasn’t much help. Putting in homemade magnetic uncoupler in various combinations brings up over 1,000 hits in each case. And for the most part these have nothing to do with the sort of hand-held wand similar to the Rix unit.
So it’s a bit of a mystery if there’s any prior art here. If anyone has a working link, it would be appreciated.
Well, you’ve had better luck than I have. I’ve gotten zero to two hits on various variations, the hits being product reviews.
Seems to me it shouldn’t be too difficult to make something and I bought some magnets at Radio Shack and have messed around a bit without any luck. Perhaps a certain strength is needed or something.
Go to the right hand column, go down to Search our Community (not the search at the top of the column). Type in “rare earth magnets” and make it search “entire community”. The 7th one down (12-31-10, I think), as it came up for me, has a good description. I didn’t look up the entire conversation, but I seem to remember that one as being quite interesting.
Sorry, I don’t know how to link it directly.
Good luck,
Richard
I only have 2 spots on my layout with uncouplers. Both are under the scale tracks on each end to uncouple and hold the cars still while it is being weighed. I used these doubled up under the track buried in the sub road bed. http://www.radioshack.com/product/index.jsp?productId=2102689 They work about 85% of the time. If I did it again I would use more powerful magnets such as the rare earth type the same size. Like one of these. http://www.kjmagnetics.com/proddetail.asp?prod=BX084
Hope this is what you need.
Pete
You might want to check out the S&L Enterprises Totally Hidden Uncoupler System that’s available from M.B. Klein (www.modeltrainstuff.com), as well as others. The N scale starter set is $5.19. It consists of four rare earth magnets (3/16" diameter x 1/16" thick placed on an 18 gauge (1/16" thick) steel mounting plate. This assembly slips under the track. There was a review article on these uncoupling units in the “Model Railroad News”, September 2007 by Phil Scandura in which he talks about the installation of the units and fine tuning them for performance. I’ve tried one of these units and they seem to be fairly reliable. I plan to use them on tracks that are not easily reached for manual uncoupling. The Rix Uncoupling Pick seems to work very well on cars whose couplers can be seen.
I tried the Radio Shack ceramic magnets (#64-1879) and found them not to be strong enough to uncouple MicroTrains N scale magnematic couplers.
Rare earth magnets are very strong, so very small ones will do the job. See the K&J Magnetic website, mentioned above, for good general information on the rare earth magnets. They seem to be an often referenced source for these types of magnets. I’ve placed one order with them and they seem to be reliable.
Bob
I use some rare earth magnets that are about 1/8" dia and 1/2 to 3/4" long. I drill two holes just inside the rails between the ties. Then just push the magnets down flush with the top of the ties. You must make sure the poles are opposite each other. These work great and the only drawback is they are providing a narrow ‘window’ of operation. I plan to mark them with some warning sign or other marker so you know where they are. I don’t glue them in so they can be removed easily if you change your mind. They are also easy to install after the ballast is in place and you realize you found another location that needs them. I prefer these to the ‘plate’ magnet uncouplers I already had as they don’t capture a set of wheels and hold them over the uncoupling plate, especially some of the lighter cars with metal wheelsets.
-Bob
Everything this guy said. Except I used the 3/8ths long ones. These ones http://www.kjmagnetics.com/proddetail.asp?prod=D26
OK, some good info here. But I must admit I am not quite sure how these things work. I mean, I get the mechanics of how you use them, but what exactly is the magnet doing? My impression is that the magnet is pulling the gladhand things off to the side. If so, the 2 magnets on each side of the track sounds like a good deal. However, one magnet seems to be also used. I also assume that the magnet or magnets need to be rather strong. How do you know in advance if a certain magnet will be strong enough?
Would those little 1/8" numbers work on HO as well as N?
It works by magic! I think you’re correct about the two pins on the underside of the couplers being pulled to each side by the magnetic field created by the magnets. There was an article about dual-magnet uncoupling by Charles Davis in the November 2008 issue of Railroad Model Craftsman on page 83 in which he describes using the K&J Magnetics D24 cylindrical magnets which are 0.125" in diameter x 0.25" long. He also describes how to fine tune the couplers for optimum uncoupling performance on page 86 of his article.
In a post on April 16, 2011 in the Forum on the Model Railroad Hobbyist on-line magazine (www.mrhmag.com), Davis suggests using 1/2" disc magnets rather than the cylindrical ones he used in his earlier article. He also included a YouTube video that he made showing how the magnetic uncouplers work on his layout, which was very impressive. Go to the www.mrhmag.com website and do a search using his name, Charles/Chuck Davis. I think I found the post by searching under “rare earth uncoupling magnets”.
I don’t think you can tell in advance what size magnet to use other than to go by what others, such as Davis, have have used. I bought several different size disc magnets 1/8" thick from K&J Magnetics to test in my N-scale application. I’ll post the sizes I used here later. I found them all to be too strong. They would pull the both couplers to the same side and not uncouple. The 3/16" diameter x 1/16" thick disc magnets when used with a 1/16" thick steel plate that are used in the N-scale S&L Enterprises unit seem to be the right size for N-scale. They also make an HO-scale version of their uncoupler unit which may use different size magnets.
There’s appears to be a fine line between magnets that are too strong and those that are not strong e
As a follow-up to my last post, the sizes of rare-earth magnets that I tried were: 3/8", 5/16" and 1/4" diameter x 1/8" thick. When used as described by Chuck Davis with one magnet under each rail, even the smallest 1/4" diameter magnets were too strong. I used the 1/8" thick magnets because the cork roadbed that I used under my N-scale track was 1/8" thick.
Using the arrangement similar to the S&L Enterprises unit, you can cut a slot in your cork roadbed wide enough to accommodate the steel plate with the attached disc magnets. You can then slip it under the track because the unit’s height is just slightly less than the height of the N-scale cork roadbed. You can then move the unit and /or the magnets around until you’ve optimized the uncoupling function and then glue it in place. Also this arrangement allows for easier removal of the unit if necessary.
Bob
A couple of points of clarification here that will help make things a little more clear.
One is that I think we’re talking about two different things here. One is how under the track, (semi-)permanently installed magnets work.
The other is in regards to making a home-made version of the Rix magnetic uncoupler wand.
As for how things work, the single under the track magnets, like Kadee’s, have a field that, when centered properly, causes the “gladhands” to repel each other. For the Rix-type handheld uncoupler and the under the track installs that involved magnets under each rail, the gladhands are attracted to the magnet on each side. Or at least that’s what I remember from high school physics.
I don’t believe that the original poster made it clear what he was interested in making. Since I don’t believe that he referred specifically to the Rix magnetic uncoupler wand, the assumption was made that he was interested in using under-track magnets to do the uncoupling. This is the reason that I and others have spent the time giving information on the rare-earth magnets which appear to work reasonably well in this application.
On my own layout, I plan to use the under-track rare-earth magnetic uncouplers only on those tracks that I cannot easily reach or see. Everywhere else, I plan to use the N-scale Rix Pick for manual uncoupling.
I have heard and read that the Rix magnetic wand uncouplers do not work very well, especially if you can not bring the wand down next to the couplers, e.g., where you have diaphragms between passenger cars.
Bob
Bob,
No problem, just wanted to help the discussion along by sorting out the varieties of homemade uncoupling apparati. I just hoped the differentiation I pointed out might help explain how these things work for those considering doing some magnetic hacking.
I’m going to grab some neodymium magnets this weekend, then try cutting a a handle out of 1/4" plywood or masonite and attaching the magnets with hot glue. The critical thing is going to be the measurements right to place the magnets just right to open the couplers.
Yes, I’ve read both good and bad about the Rix wand. Based on that, the key seems to be getting some slack, which the prototype has to do when they uncouple. Those who mention this factor seem to find the Rix works for them. However, if there are diaphragms with enough tension that they are pushing the cars slightly apart, that would be something that keeps you from getting slack.
Fortunately, I’m primarily a narrowgauge modeller and what standard gauge passenger equipment I have tends to stay coupled. However, if I ever upgrade the details on my San Juan to include the diaphragms, then this could be a factor. I don’t do much passenger switching, so it may not matter to me as much as the convenience it’ll bring to freight switching – presuming I can hack something together that works.
To make things clearer, I am interested primarily in the under-track style ucouplers. To be perfectly honest, I didn’t realize there was this wand thing, although now that I know such a thing exists, I might find some use for it.
I read somewhere that a guy used the magnets off his used Sonicare toothbrush heads for uncoupling. I have been saving these since I read about how strong they are. They are very strong little magnets and I sometimes need to use pliers to pull them apart. I have yet to try them at uncoupling.
Brent[C):-)]
Within the last year or two Railroad Model Craftsman had an article on making a magnetic uncoupler that “retracted” using a tortise or some switch machine. The sleve it raised and lowered in was made out of a paint stirrer. Looked like a very elegant was of having an as needed magnetic uncoupler.