Working MU cables?

[samusi01]

Years (decades?) ago in MR a modeller a fellow MUd some HO diesels.

An issue in the mid 90's as I recall. Possible with a b&w photo accompanying the article?

[peteski]

Yes, those machined (and usually gold plated) pins Rod uses are very reliable.  They are used in high reliability electronic connectors and chip sockets.

Not sure what size pins Rod uses, but the smallest ones I found were removed from 0.05" pitch connectors.  I also have larger pins from 2mm, and 0.1" pitch connectors.

[Angus Shops]

In moments of fantasy I’ve wondered about some sort of micro-magnetic connector... practically automatic when coupling and fully ‘pull apart’ auto when uncoupling. Didn’t some manufacturer in some scale offer a magnetic brake line hose?

[ednadolski]

Didn’t some manufacturer in some scale offer a magnetic brake line hose?

http://mattforsyth.com/wp-content/uploads/2010/06/Ben-Browns-Mag-Hoses.pdf

[learmoia]

Years (decades?) ago in MR a modeller a fellow MUd some HO diesels. Brass tube in each pilot. For the MU cable he used phosphor bronze wire bent into a horseshoe shape. The small tips fit in the tubes. They bend as the loco corners. The pressure of the horseshoe shape maintains contact. He maybe have bent the ends like a bobby pin to make more of a friction fit in the tube. I can’t recall. Simple design. Might work.

Craig.

I vividly remember that article..  (not what Month/Year).. but its one of those things that I can clearly remember the illustrations in my head from 30 years ago, yet I can't remember anything else.
 
He had either a 4 or 6 wire system simulating the air hoses on each side of the coupler , and each locomotive had some form of diode matrix to current correct the power between the locomotives because it was Pre-DCC so either he was trying to have a bi-direction connection that didn't matter what what direction the locomotives were oriented. 

It seemed like overkill to my 10 year old brain.. but there was some odd reason he thought he needed more than 2 wires and a diode matrix..

~Ian

[Mark W]

So, define "detachable".

Detachable regularly, or just for occasional storage?

For me, detachable is defined as non-destructive.  I found that PBC ties fit quite snugly between frame halves.  I have to remove the couplers to connect or dis-connect them, but when connected, these are my most reliable units by far.  Of course, this only works for split frame mechs. 


https://i.imgur.com/7xcaEWV.jpg

[nkalanaga]

In my case, 1/32 inch brass tubing and 0.02 inch brass rod, with very flexible "disk drive read head wire" for the cables.  These were 1960s disk drives, so where would find such wire today I have no idea.  I'm sure a substitute could be found.

Drill holes in the pilot, one on each side of the coupler, for the tubing.  On the back side, solder a wire (whatever you like) to the outside of the tubing, and connect it to the loco somehow.  Mine were split-frame locos, the early Atlas/Kato units, and the Kato GP-38, so I just jammed the wire between the frame and the body, easy to remove if needed.

For the jumper, take a piece of the brass rod, long enough to go through the tubing, with about a 16th of an inch left over.  Wrap the flexible wire around the pin end and solder it.  It should stick out at a right angle to the pin.  Do the other pin the same way.  Wire length is trial-and-error, based on curve radius and pilot spacing.  When done, the wire will hang down in a loop between the two pins.

Put a slight bend in each pins, so it stays in the tubing, and install the jumpers.  Works great, costs very little, and they're easily removable.  On the outer ends of the consist the tubing is almost invisible, as it doesn't have to stick out past the pilot.

On my Trix and Kato F-units, which had truck mounted couplers, I put the wires directly between the frames.  In the Kato, they were jammed between the frame and the body on both ends, on the Trix, one end was soldered to the insulated-side PC board, under the motor.

[randgust]

Wow, thanks guys.   

On those magnetic brake hoses - I had a custom build where I put those on.   Wow, those are difficult to assemble, they did work, but honestly, between a couple units and under the coupler it was a whole lot of work without much visible reward.   It was a 'gee whiz' to watch them disconnect and reconnect, but...

You'd have to have an eye-level layout to justify those.

I've been looking at the brass-tube and wire plug idea, but using 1/32 tube...hmmm..... who's got that stuff?    As you can see on the Jamison project, I can do a lot of work with brass shapes, that was all brass wire and tube construction for the pump jacks.

I've used those Miniatronics plugs on several things, but two issues remain - first, they are kinda pricey, and second, I think those wires are darn stiff and you'd do better with the stranded #22.    I used one of these on the tender connection for the Jamco 4-6-2, it works, it's detachable, but I took as much of the stiff wire out as I could and replaced it, so it seemed like kind of a waste of money.    I have used them on a lot of building and lighting projects so that I could easily get the building out for maintenance and cleaning.   

I figure I'll have to reach in with tweezers to plug and unplug but that's fine.   I'm also thinking that if you'd alternate; i.e. one side male and the other side female - you'd be better off than if both ends of one unit were male and the other end female.   That #22 flex stranded wire in the black insulation is what I'd use, it's as flexible as anything I've seen.

[garethashenden]

Didn’t some manufacturer in some scale offer a magnetic brake line hose?

Still in stock, $35 for 10 pairs: https://www.pwrs.ca/view_product.php?ProductID=214181

[ednadolski]

Still in stock, $35 for 10 pairs: https://www.pwrs.ca/view_product.php?ProductID=214181

Drift alert:  It's +10 years since I bought anything from PWRS, do they still do that annoying purchasing account thing and the incessant sales calls?

Ed

[Ed Kapuscinski]

So here was my thought on this. If you want to improve contact, you don't need MU cables that are 100% perfect, you just want ones that improve things substantially.

To that end, I'm thinking what about using some brass tubes that some wires can insert into and rely on their contact. With 3 on each side you'd probably be fine.

[nkalanaga]

My 1/32 inch tubing came from Special Shapes, which seems to be out of business.  I'm sure there's somebody on the internet selling it, maybe one of our scratchbuilders can point us to them.

I got a three foot piece, and used maybe three inches, before flywheels made it generally unnecessary.

[Simon D.]

I got some 1x1mm magnets in the UK, but these are even smaller:

https://www.ebay.com/itm/TINY-1mm-Neodymium-Disc-Strong-Magnets-Rare-Earth-Neodymium-N35-Super-Strong/333227700197?_trkparms=ispr%3D1&hash=item4d95eb2fe5:g:OGcAAOSw1opbbCZP&enc=AQAFAAACcBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkCrLl8erj3ATP5raQxjc%2F%2Bys81PC%2BP9m2PlxMRFk2nKOLrYw1ypgBYO9WRNOS1wzwl58y%2FiroBtVCKSRujVj8exRlAOJSf2tgOBW0mdsEuwrDmVF3XWBYEdS7xHzu16FXJUsDCwYbYjUPiwxo3KiPge6gB9ubUXSFa0HpRprhQQYN0FPL2Knoo2tln4jCDD6sssaoXiHdR1%2FO7Hv%2F3%2BTLXPNBQCgM5l9ALd0DASbPAE%2B5sS%2BCr4AxTIrZ7wcQRUdHu4KGgYV7srl9n%2FwmxXUc5kgfN8Uzlx9xW7PiLNJyuf8AloK5nYsZnEhRKuj5NJxp0MersrTQ2vnkgZPOV%2F%2FdwlKVvzvP1UkM2No8AVhXuUi52Fiv6Er1hi6Z1mE2w3GcCto%2FYBOGKVqF3A8oQAjinr2yqSts2aTdseez7Dlz9%2F0PCi%2B9HfXXMBBaj2tULyfI4g05b%2B3Ec9skvb6D3sZdyi8TRrvEvJ%2BORyI6K9%2FilLasebKxs3sqM%2FTmK6kVW%2FlfgGt1%2BVssRScJ0NoFZz7Dv%2F3Tc%2B4Npkqbj6c1ULEHmIEYkBDRI05w7c8ojGA5pGzWqY5vo9dVV%2FD7hNroGIvUQJrc43HgkzOF5p%2BxGTzP35457ZvDHN8zuvPRRoie9Bhc5soLdMynac96vtb93GSo6zffnwDE%2BIUbavcBNKDj6yyXxUFIM5BZZ32kycnG6ULiEGXCdzoAyoCD%2BcJe2To3syBbGhM7GHs3LDT5qAzglIwt4NAKs0ptkrlodeiErwIKLn56LDqTa2LLb181CW%2B9Mw%3D%3D&checksum=333227700197f6481a15d1294eadb6861124680540e8

[NtheBasement]

My much-loved but quirky 1982 Kato GP38 has always been plagued with pickup problems and it's in the design. 

Before you do the surgery... is this one of those locos where a truck could be on backwards?  It makes the wipers miss the contacts.

[ChristianJDavis1]

Before you do the surgery... is this one of those locos where a truck could be on backwards?  It makes the wipers miss the contacts.

No wipers on the 1982 Kato GP38-2: truck halves rub directly on the frame halves to transfer current. This current transferring scheme is a lot less reliable than the modern wiper method.