Couplings

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ge_rik
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Re: Couplings

Post by ge_rik » Fri May 04, 2018 2:40 pm

philipy wrote: Fri May 04, 2018 10:42 am An inverted version of the Slaters one but with the 'body' members slghtly wider apart to allow some sideplay for the hook, wouldn't be difficult to knock up and you could then make the face of the buffer as wide as you need to prevent buffer lock.

Edited to add: There is a beastie called a Dingham Coupler. I admit that I've no experience of it but it might help either directly or simply to give you ideas.
http://www.dingham.co.uk/7mm_coupler.htm
They're very neat and quite cheap. Only problem is that I have a reverse loop on my railway which I use from time to time and so some stock would end up the wrong way round. Pity, I like the delay option for uncoupling.

Rik
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Re: Couplings

Post by ge_rik » Sat May 12, 2018 3:30 pm

I've been doing some experiments and made some progress on developing my own couplings. I decided that the easiest approach was to produce something which would be a direct replacement for LGB couplings - so same dimensions and same single screw fixing. At the moment, they are very much prototypes - I've ordered some brass rod/wire and more brass plate - oh and some chemical blackening solution.

At the moment, just a couple of paper-clips soldered to a bit of bent-up brass. I'll improve the fixing pedestal as well.
IMG_7561.JPG
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The hooks engage in the same way as the original LGB versions.
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When pushing, the Binnie Carmarthen couplings bear against each other. I've checked them over the sharpest curves and there's no buffer lock.
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The beauty of this coupling is that it is compatible with LGB coupings and so I can replace them over a period of time and run original and new couplings together.
IMG_7563.JPG
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I'll post more info once I've made up some 'proper' versions.

Rik
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Re: Couplings

Post by tom_tom_go » Sat May 12, 2018 3:34 pm

Agree with blackening these using chemicals rather than painting as it will not last.

I don't see how these uncouple though without having to bend the wire down?

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Re: Couplings

Post by ge_rik » Sat May 12, 2018 4:33 pm

tom_tom_go wrote: Sat May 12, 2018 3:34 pm I don't see how these uncouple though without having to bend the wire down?
Yes, that's right. I'm using the springiness of the wire to provide the auto coupling effect and then pressing the hooks down to uncouple. Same principle as LGB couplings. That's why the hook is soldered further back than the loop.

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Re: Couplings

Post by bazzer42 » Sat May 12, 2018 4:55 pm

Having said keep the lgb coupling they look quite clumsy against your home made version. With blackening they will virtually disappear, clever!

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Re: Couplings

Post by IanC » Sat May 12, 2018 6:32 pm

Rik,

With a little modification the hook can be made to pivot downwards to facilitate uncoupling. It would also enable auto uncoupling if you want to add that later. It would just need a magnetic dropper. I used to use florists iron wire. Available for a few pence and already blackened too! As wire lacks depth my friend soldered a vertical piece of wire to the bar to prevent any locking issues.

Looks promising and the finished version will be better that the LGB ones.

Ian
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Re: Couplings

Post by philipy » Sat May 12, 2018 8:05 pm

Rik,
That does look good and it also looks as though you could add a dropper ball like Tom's, to allow the delayed magnetic uncoupling?
Philip

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Re: Couplings

Post by tom_tom_go » Sat May 12, 2018 8:34 pm

I think hands free uncoupling will improve your operating experience Rik.

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Re: Couplings

Post by GTB » Sun May 13, 2018 5:34 pm

ge_rik wrote: Sat May 12, 2018 3:30 pm I've been doing some experiments and made some progress on developing my own couplings.
That was quick. Well done, I think you've cracked it.........

Just need to knock off the rough edges now with a pre-production batch and make up some bending and assembly jigs to make sure they all come out the same.

If you can find some suitable size phos bronze wire it is more springy than the same dia. of brass wire, but just as easy to solder. With more flexible hooks, the couplers would need less force to couple them up.

Regards,
Graeme

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Re: Couplings

Post by ge_rik » Sun May 13, 2018 7:46 pm

GTB wrote: Sun May 13, 2018 5:34 pm If you can find some suitable size phos bronze wire it is more springy than the same dia. of brass wire, but just as easy to solder. With more flexible hooks, the couplers would need less force to couple them up.
Regards,
Graeme
Hi Graeme
Still needs some refinement but the principle seems ok. Got some phosphor bronze on order and some heavier gauge brass wire for the loops - the paper clip loops are a bit too easy to bend out of alignment.

I was hoping I could get away with using the centre buffers on my 'bashed' LGB stock but they aren't wide enough and have a tendency to lock when being propelled. Looks like I'll either have to find a way of widening them, with plasticard or brass shim, or replacing them with Binnie Carmarthen buffers.

Rik
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Re: Couplings

Post by gregh » Mon May 14, 2018 12:39 am

ge_rik wrote: Sun May 13, 2018 7:46 pm I was hoping I could get away with using the centre buffers on my 'bashed' LGB stock but they aren't wide enough and have a tendency to lock when being propelled. Looks like I'll either have to find a way of widening them, with plasticard or brass shim, or replacing them with Binnie Carmarthen buffers.
Rik
Have you looked at these Pasidump brand? If you only need them to push, they might be OK.
https://www.ebay.com.au/itm/152805495920?rmvSB=true

Being a rough-as-guts modeller, I'd just use a piece of wood like these on my rake of coal wagons that I rarely uncouple. (I use chains on the nail you can see)
buff.jpg
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You could shape them better than me, I'm sure.

I certainly wouldn't use plasticard shims - breaks too easy if you do manage to lock buffers. Brass would be OK.
Greg from downunder.
The Sandstone & Termite's website: https://members.optusnet.com.au/satr/satr.htm

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Re: Couplings

Post by ge_rik » Mon May 14, 2018 7:42 am

gregh wrote: Mon May 14, 2018 12:39 am Have you looked at these Pasidump brand? If you only need them to push, they might be OK.
https://www.ebay.com.au/itm/152805495920?rmvSB=true

Being a rough-as-guts modeller, I'd just use a piece of wood like these on my rake of coal wagons that I rarely uncouple. (I use chains on the nail you can see)
buff.jpg
You could shape them better than me, I'm sure.

I certainly wouldn't use plasticard shims - breaks too easy if you do manage to lock buffers. Brass would be OK.
Hi Greg
Yes, I did get a pack of those when I was going through the evaluation phase. I'll dig them out and see how they look. I'm struggling to get a response from Peter Binnie - may have to wait for Llanfair before I can get more Carmarthen buffers.

You're right, brass shim will be better than plasticard.

Rik
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Re: Couplings

Post by GTB » Tue May 15, 2018 6:19 am

I'd agree with Greg, plastic buffer extensions wouldn't survive the first derailment.

I'm not sure a glued joint between a metal plate and a plastic buffer would be that strong either, although you could try 'Loctite Super Glue All Plastics'. It comes in two tubes and uses a surface activator as well as glue.

A shaped block of wood has a lot going for it. The easiest way to make a lot of them to the same shape is to shape a stick of wood to the desired cross section from above, then cut off slices to make individual blocks.

Another alternative is to use a buffing plate in front of dummy buffers like the example below, which can't buffer lock and is fixed with screws.

Extended buffer.jpg
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This was knocked up in a few minutes, which was quicker than trying to describe it in words. It looks ugly and the shape needs refinement.

It occurred to me afterwards that a piece of wire bent into a U, recessed flush with the buffer face and glued into holes in the buffer beam would do the same thing and would be a lot less obtrusive.

Something like this would work well for bogie vehicles with long overhangs and also at the rear of locos with a long rear overhang.

Regards,
Graeme

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Re: Couplings

Post by ge_rik » Tue May 15, 2018 7:21 am

Thanks Graeme
I like to idea of a wire loop over the buffer, as you say, less obtrusive.

Had a PayPal invoice from Peter Binnie last night so, hopefully, will soon take delivery of 60 Carmarthen coupling hooks. Together with my existing supplies, that will be sufficient for half my rolling stock. I'll experiment with ways of widening the LGB buffers, but at 50p each, Carmarthen buffers are a cost effective alternative.

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Re: Couplings

Post by ge_rik » Tue May 15, 2018 11:19 am

More progress. All the bits and bobs I ordered over the weekend have arrived and so I've had a chance to try out the new materials. 1.5mm brass rod for the loops and 0.7mm phosphor bronze for the hooks.
IMG_7573.JPG
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I've done some testing and this arrangement seems to overcome some of the problems I was having previously with the loops becoming misaligned and the hooks not springing back after a few uncouplings. These are the prototypes and so look a bit rough and ready. As soon as the Binnie buffers arrive (paid for this morning), I'll be able to go into proper production.
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I've had a go at chemical blackening. Seems a bit hit and miss at the moment. Might need to practise a bit more before I get the process perfected.
IMG_7575-001.JPG
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Getting closer!

Rik
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Re: Couplings

Post by tom_tom_go » Tue May 15, 2018 11:59 am

They look better Rik.

Chemically blackening requires the metal is be clean (I normally go over with wet and dry paper).

Don't dunk the metal in the solution, use a brush and do several attempts cleaning the metal each time with water.

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Re: Couplings

Post by ge_rik » Tue May 15, 2018 4:46 pm

tom_tom_go wrote: Tue May 15, 2018 11:59 am They look better Rik.

Chemically blackening requires the metal is be clean (I normally go over with wet and dry paper).

Don't dunk the metal in the solution, use a brush and do several attempts cleaning the metal each time with water.
Thanks - will get scrubbing after I've done the soldering.

Rik
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Re: Couplings

Post by GTB » Thu May 17, 2018 2:49 pm

ge_rik wrote: Tue May 15, 2018 11:19 am I've had a go at chemical blackening. Seems a bit hit and miss at the moment. Might need to practise a bit more before I get the process perfected.
As Tom said, brass needs to be very clean before blackening it. Degreasing helps as well. Also remember to rinse the parts when finished, or the black coating can turn powdery,mwith salts on th surface..

What you use for cleaning depends on the shape of the part, I often use a fibreglass pencil to get into places sandpaper can't. A scrub with Ajax helps clean and degrease the metal as well as neutralising any flux.

Not sure where I got the idea, but using a cotton bud (swab) to apply the blackener by rubbing works for me. Sometimes you just have to dip the piece though, eg. brass chain.

Carrs used to do a solution for blackening solder, but I'm not sure it is still around. You may need to paint that area, as normal blackening solutions only work on brass and steel.

Regards,
Graeme

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Re: Couplings

Post by tom_tom_go » Thu May 17, 2018 3:25 pm

Cotton bud, will take that idea!

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Re: Couplings

Post by philipy » Thu May 17, 2018 4:21 pm

I usually use a cotton bud, I thought everyone did?

BTW,I have n old bottle of Birchwood Casey Gun Blue which works for blackening on ferrous and non ferrous metals without too much bother. Actually produces a sort of dirty/rusty brownish black colour, not blue at all. Perfect for axles, and various other underframe bits and pieces. I usually clean the metal and then slosh it on and leave it to dry ( not what the instructions say though!). I think I probably got it from Eileens Emporium, way back in the days of Eileen herself!
Philip

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