Kadee Magnets

Is there anything special about the Kadee uncoupling magnets, they appear expensive. Is there a cheaper way?
TIA Dobbin

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Dobbin wrote:

They are magnetised crosswise. This makes them "special production." Bachmann also offers them, somewhat cheaper. Magnetic latch magnets will work as under-track magnets, but you don't get as long an uncoupling ramp as with Kadees.
Cheers, wolf k.
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Take care if you get magnets made of neodymium-iron-boron, which are shiny & silver in colour, and are near anyone with a pacemaker or implanted heart device as they can destabilise them !!!!!!!
Chris
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wrote:

It is nothing to do with the material that the magnet it is to do with the intensity of the magnetic field and the proximity of the magnet. Any of the rare earth magnets may well produce a high enough field if you put them in your shirt pocket!.
Jeff
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Just another form of uncoupling I suppose. ;o)
--
Keith W
Sunbury on Thames
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Dobbin wrote:

Long-ways pole rather than cross-ways.
I've used the O-gauge ones cut in half underneath the trackbed of N track very successfully. I've also mounted them on hinges to swing away the magnet in situations where accidental uncoupling was happening (pulling a train very slowly onto a sharp curve).
I'm sure its possible to do them cheaper with modern rare-earth magnets and a few bits of steel to create suitable poles and magnetic shunts. But its not on the first sheet of "experiments I ought to try out", so someone else will have to report back on how to do it.
- Nigel
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Nigel Cliffe,
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<snip>
I have been tinkering with a number of different uncoupling methods in N gauge with a marked absence of success. You wouldn't care to go into more detail would you.
--
Keith W
Sunbury on Thames
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On Fri, 24 Jul 2009 14:43:11 +0100, "Keith W"
Keith,

I've also been messing around with remote uncoupling MT couplers in N scale. I've not really had much success with permanent magnets, whether that has been the MT products or making up magnets using various combinations of small button magnets.
The main problem has been involuntary uncoupling since the lighter N scale stock can start bouncing when being pulled and allow enough slack for the couplings to operate. I haven't tried Nigel's hinged magnet setup to overcome the problem.
Another problem I got with my US bogie stock was that the strength of the magnets necessary to operate all the coupler types I have - MT, Accumate and McHenry - would sometimes pull truck mounted couplings down as well as across, and derail the truck.
I've now gone for electro-magnetic operation and I'm using the guts of old Carpenter relays to provide the bits. The Carpenter relays have a U shaped pole piece with a coil on each leg. The width across the pole piece ends is just about right for N scale. The considerations I have with this system is that the flux generated by the relays is just about sufficient and will only operate well made MT couplers and the new McHenry N scale couplers (on new Athearn stock). I've given up trying to make Accumates work well since their centring springs are quite stiff and require a lot of magnetic oomph to get them to operate reliably. I'm also changing out all the truck mounted couplers to body mount MT 1015s where I can to get rid of the Accumates on Atlas stock. I have to assemble the 1015s quite carefully with plenty of burnishing and graphite to make sure the work well. ready built MT couplers work well, but are a bit pricier.
I use a 50V supply to operate the relay coils (their design voltage) and I've rigged up a simple capacitor discharge system to give a 60+V pulse at the start to get things moving.
I've actually been quite surprised at how difficult it has been to get a reliable working remote system with N scale knuckles. I'm building a switching layout and progress on the track laying has been held up for a long time until I thought I had cracked the coupler operation. At present, I think I have got a working system. I can see why a lot of people recommend using manual methods with toothpicks (or whatever) but I didn't want to use manual methods on my layout.
Jim.
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Jim Guthrie wrote:

I started using hinged/pivoted magnets to overcome the problems you report !
One other trick which may be worth exploiting if using DCC.... The chips from Zimo, CT and the new "+" models from Lenz support "uncoupling". Whilst meant for DCC controlled couplings (eg. Krois, or the ones I keep building), the movement features alone for the loco will give a function key which will produce the "Kadee Shuffle" to uncouple and then re-engage in "propelling" mode.
- Nigel
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Webmaster at http://www.2mm.org.uk/
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On Sun, 26 Jul 2009 13:15:33 +0100, "Nigel Cliffe"
Nigel,

I didn't tell the whole story :-)
I experimented with several styles of magnets, including the official MT one, and I couldn't get reliable uncoupling. I wanted the magnets completely hidden underneath the track and I couldn't seem to get anything to work reliably with them under the sleepers - even thin PCB sleepers. So I didn't proceed further with the hinge idea.
My Carpenter relay guts seem to work quite well but are quite sensitive to the quality of the knuckle and I can only reckon on good operation with MT and McHenry couplers and carefully built MT coupler kits. The shape of the magnetic field seems to suit the couplers and I don't seem to get problems with a vertical component to the coupler movement, which was my main problem with permanent magnets which seemed to pull couplers down as well as across and cause derailments.
I also tried some of the MT between rails magnets on a shunting plank setup, and they were a disaster since they pulled the couplings down till the operating arms stuck to the magnets with bogie mounted couplers. I might try them again with body mounted couplers to see if the problem still exists with them.
Jim.
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Jim Guthrie wrote:

If wanting to experiment further, try the O gauge Kadee magnets below sleepers. In my case the arrangement is: Hinge, backing plate, magnet, card (or thin ply), Peco Code 55 N gauge. The magnets also work fine under Peco turnouts (in the blade area, not the crossing V!). In most cases I cut the O gauge magnet and backing plate in half. (I'd have to dig around under the layout to work out which way the cuts went !).
I have found the MT N magnets to be troublesome, having most of the problems you report.

I do get some vertical pull, but it only affects one vehicle where the coupling body isn't properly glued into its housing, so the coupling can pivot downwards. Easily fixed with some superglue !
- Nigel
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