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Sprat & Winkle couplings


Mikkel

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Shunter George "Bulldog" Mullins critically eyes stock fitted with Sprat & Winkle couplings.

His shunter's pole is legendary among shunters for being rather crude!

 

The following notes on Sprat & Winkle couplings seemed to generate some interest when first posted over on gwr.org.uk, so perhaps they are of of use to someone here also. I have taken the opportunity to take some new and better photos for illustration.

 

 

Hooked

 

Although the latest RTR offerings have helped enhance the looks of the RTR tension-lock coupling considerably, I still find them a bit too bulky and not quite reliable. They also do not offer the opportunity of "delayed action" uncoupling, which allows you to propel stock forward after uncoupling.

 

Looking for an alternative, I have taken to the fairly well-known Sprat & Winkle coupling, which - although a compromise in some respects - has proved quite reliable and fairly easy to fit. I find the delayed-action feature of these couplings simple and effective, and a plus for me is that they allow cosmetic 3-links to be retained.

 

 

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Hook and bar. It could be argued that it is no less obtrusive than the modern tension-lock coupling.

But I find it less bulky and with more functionality.

 

 

One-hook operation

 

The Sprat & Winkle couplings are available in 2,3,4 and 7mm scale versions. As I model in 4mm my choice was between either the standard 4mm version or the "finescale" version. The latter is in fact intended for 3mm modellers but works fine for 4mm (including OO), as long as your curves are not too severe ( ie less than 4' radius according to MSE). This is fortunate because the standard version is a bit on the large side for my liking, and so I have opted for the finescale/3mm version.

 

In fact, even the finescale version is a bit more prominent than I would personally have wished for, especially when uncoupled. To minimize the visual impact I therefore fit a coupling hook to one end only, adding just the loop at the other end. This obviously requires stock to be facing in a particular direction when placed on the track, but on my layouts (and I think many others) this isn't really a problem. The absence of a coupling at one end also facilitates the fitting process (since you only have to fit one hook per wagon) and means I can add a prototypical (but cosmetic) coupling hook here instead, enhancing appearances a bit.

 

 

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Coupled up using the "one-hook" approach

 

 

Mounting the couplings

 

The coupling hook features a square "paddle" at one end, which works as a counterweight beneath the wagon or coach body. The MSE website has an instruction sheet for fitting the couplings, and details on various extra parts not described here (including custom-made mounting plates). The instructions suggest two possible ways of mounting the hook: An "Upper" method in which the coupling hook is inserted through the headstocks (ie the "buffer beam" of the wagon), and a "Lower" method in which the hook rests immediately below the headstocks, hinged to the wagon floor with wire bent to the shape of a paper staple.

 

It is necessary to standardize on one of these two methods, and in principle I prefer the latter, which also comes recommended in the instructions: This requires only minor modification to the wagon or coach body, and is also - in my opinion - rather less fiddly. That said, I have made two minor modifications to this approach:

 

* Firstly, I replace the curled-up wire included in the pack with straight brass wire from Alan Gibson. I find that this makes it far easier to craft the wire-staple needed for fitting the paddle. The staple is then fitted to a section of square plastic rod mounted on the wagon floor. The plastic rod is not always necessary - it depends on the distance between the floor and the lower edge of the headstocks.

 

* Secondly, I find that the "Lower" method of mounting the coupling can sometimes give problems in ensuring that the coupling hook is fully horisontal: Exactly because it is underhung, the hook may come to rest at a slight upward angle against the bar of the loop on some wagons, which is neither aesthetically pleasing nor good for operation. I don't think it's just me, as I have heard others mention this issue also. My solution is rather crude I suppose, but effective: I simply open out a slight slot in the wagon just above the coupling hook, thereby allowing it to move freely to a full horisontal position against the loop. This may not be to everyone's taste, but the slot is really quite unnoticeable and can always be padded over with a filler if the coupling is removed.

 

 

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The "Paddle", anchored with a wire "staple" to a supporting section of plastic rod

 

 

 

Un-coupling

 

Uncoupling is by means of magnets located beneath the track, nested into the track base. The magnets attract the 3-links, thus tilting the hook downwards. When moving back up, the hook comes to rest in a position which allows the wagon to be propelled forward and left where you want it in the siding. Hence the "delayed-action" concept. The following photos illustrate the four main steps of this process:

 

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1. Wagons are propelled in fully coupled condition

 

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2. Coupling hook drops down as it is attracted by a magnet beneath the tracks

 

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3. As wagons are propelled forward the coupling hook moves back up, but does not fully engage the bar

 

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4. The uncoupled wagon is left where desired, and the rest of train is drawn backwards

 

For me this works well, with one important modification: Because I use only one coupling hook, the very powerful magnets occasionally uncouple the stock even when they are not supposed to - ie when the stock is passing slowly by. This happens even with a good layer of ballast above the magnets, and attempts with a sliver of Plastikard above the magnet doesn't help much either.

 

Again, I resort to cave-man technology for the solution: I simply break the magnets in half, thereby reducing the overall magnetic field. I say "break" because cutting will get you nowhere with these magnets - they need to be broken in two by holding the magnet with one pair of pliers and breaking downwards with another pair. Crude stuff, but it works.

 

Finally, I should perhaps emphasize that I have no affiliation with the manufacturers, and that these are the experiments of a novice: I do not have experience with the other non-RTR types of couplings available (see jim s-w's blog for an interesting entry on the Dingham coupling).

 

Edit 1: For a discussion of fitting the couplings to locos, see the comments to this entry.

Edit 2: The video in the link below shows the Sprat & Winkles in operation on the goods depot layout:

 

Edited by Mikkel

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7 hours ago, Mikkel said:

Thanks Jeff and Michael, I will do that. I have another S&W fitting session coming up so will give it a go then (I seem to remember there was a reason I don't use the mounting plate, but I have forgotten why and it may be a myth created inside my head!).

 

In the same boat - I used them in my first go at S&W's but gave up on them for some forgotten reason and have managed successfully without them ever since.

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On 06/11/2009 at 05:44, Mikkel said:

Interesting Richard. I did initially consider leaving off the bar at the hook-end, but found that the hook would then be prone to tilt upwards (rather than remaining horizontal) . But maybe you have found a workaround to that?

 

Thought I'd better get round to replying to this one ...:blush_mini: I adjust the hook end position by bending the weighted paddle to suit. Once done it rarely need altering, usually only after a knock, and hasn't been a problem at all.

Edited by Ben Alder
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On 19/05/2019 at 12:24, JSpencer said:

I remember Sprat & Winkle when I was part of the Chatham club.

 

I am surprised that a NEM version does not now exist.  That would bring more converts.

 

It would certainly be nice, but maybe there aren't enough people who want to fit S&W couplings to RTR wagons  to make it worthwhile? A chicken and egg situation.

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Mikkel

Posted (edited)

On 19/05/2019 at 17:14, Ben Alder said:

 

Thought I'd better get round to replying to this one ...:blush_mini: I adjust the hook end position by bending the weighted paddle to suit. Once done it rarely need altering, usually only after a knock, and hasn't been a problem at all.

 

Good to know. I do find the S&Ws quite reliable, even with my fairly relaxed standards. 

 

And thanks for coming back to this. I'm trying to remember what has happened in the world since November 2009, but it's all a blur! :lol:

 

Edited by Mikkel
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It's important to ensure that the bars align, I usually set the height of these first (at 12mm above railtop) , then an just the hook, by bending gently half way along, so that the inside of the hook aligns with the bar. Also ensure that the bar is aligned with the buffer face to avoid buffer locking when propelling. I'm trying to develop a s&w coupling that will fit a nem pocket!

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Hi @Mikkel (and the 202 other followers of this blog post),

 

Sorry for resurrecting what may seem like ancient history, but I was wondering if your process has changed over time? I'm not far off fitting S&W couplings to my stock, such as it is, and was wondering if there were any hints and tips further experience has brought. 

 

A little way off scattering horse poo about the layout, but when the time comes it'll be this blog I look to for information: there is nothing that isn't improved by a trip to Farthing :)

 

Cheers,

 

Schooner

Edited by Schooner
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I'm 10 years on from my comment in this thread (eek!) and I'm still well happy with S&Ws. I think I began fitting them around 2011, I've now converted a very large proportion of my rolling stock and locos, and have no real grumbles. I use the 3mm version on 4mm stock, and routinely propel trains around 30 inch (and tighter) curves without issue.

 

I put permanent magnets on my running lines as well as sidings, so trains have to be able to run through without anything uncoupling when it isn't wanted. Now and then I do get an issue with a guard's van or similar detaching from the end of the train, but while I wouldn't say I've cured the problem 100%, I find a combination of extra weight (to stop "waggle" at the end of the train, which allows the couplings to go momentarily slack) as well as the occasional use of friction brakes on the axles, helps make the problem infrequent enough that I can live with it.

 

 

 

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On 26/05/2019 at 18:34, Theo said:

I'm trying to develop a s&w coupling that will fit a nem pocket!

 

How did you get on with this? I'd be interested to know.

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Hi Schooner, my experiences are exactly as Al's/Barry Ten's. I have also rolled them out to all wagons by now - also using the 3mm ones -  and am happy with how they work. I haven't changed the way I fit them, as far as I remember. The only issue is that I struggle with fitting the 3-links sometimes. There's a post about that here, followed by some discussion:

 

https://www.rmweb.co.uk/community/index.php?/topic/97672-pragmatic-pre-grouping-mikkels-workbench/&do=findComment&comment=3999700

 

 

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Trying not to start a new thread and this seems relevant. Two queries:-

 

1) I have a pack of what must be Mk1s bought two, even three, decades ago and not used due to (2) below. What is the difference between these and the Mk3s now being sold?

 

2) What is the minimum radius they can be used on? I had been told 3ft (which is why the set I bought ages ago have never been used) but recall seeing a recent note somewhere that a newer version exists for tighter radius curves.

 

I have used them before when helping on other people's layouts so it is only the radius issue that is stopping me - no space for 3ft curves, hence the question.

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John, my own knowledge is limited to the Mk3 couplings (I use the 3mm ones), so I have no practical experience of the difference between Ml1 and Mk3. These photos of Mk1 (left) and Mk3 (right) suggest the only difference is the shape of the hook.

 

swmk1.jpg.cae6bfc14d8455b7eddf75643964f531.jpgswmk3.jpg.36f37b228ef8f6801db96742a79ac6d9.jpg

 

As for radius, my layouts are small without much curvature, so it hasn't been an issue for me. Can others help?

 

Edited by Mikkel
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I use the 3mm Mk3's as seen above on the right - they are less obtrusive than the 4mm version and have a delayed uncoupling action, so are far more versatile. My curves are 24" with one or two yard ones a bit less and I have no problems with them, with the proviso that my stock are all handed so there is a coupling at one end only.

 

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My ruling radius on the mainline is 30 inches (although it gets squeezed a bit tighter here and there). I've got one siding which is tighter than that, so probably somewhere between 24 and 28 inches and stock has to be pushed and pulled through it during shunting. Certainly no problems with typical 4 wheel stock, up to say CCTs, and small tank and tender locos, but I've not tried pushing really long wheelbase stock through it very systematically.

 

I've occasionally had to fiddle with the couplings on the mainline where there's a loco with a large rear-end throw (such as a large prairie or Fowler 4MT) pulling some wagon or coach which also has a long throw. The solution in that case is just to make the goalpost bit as wide as possible to allow maximum deflection of the hook.

 

In general I would say there is a good chance of getting S&Ws to work on somewhat tighter curves than the quoted 30 inches. provided you're prepared to experiment and perhaps accept that some stock can't be marshalled next to other items.

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Definitive answer from the supplier is below:-

 

1) what the minimum radius is they can couple and propel at? - 2ft for the 3mm version with the mounting plates; a bit less for the 4mm version

2) what is the difference between the Mk1 and Mk3 styles? - Mk3 has the extra “hook” so you can propel after uncoupling without them recoupling.

3) do they engage on curves? -  Yes.

 

3ft was the old restriction before the modification with the addition of the mounting plates.

 

Hope this also helps others, especially the knowledge that the 3ft curves restriction is obsolete for current supplies.

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Many thanks John, that's useful information.

 

I have to say that I'm quite happy with my S&Ws, and find them quite reliable. Also easy to tweak, should one go out of alignment.

 

Just remember to always look over your shoulder...

 

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Edited by Mikkel
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I have found all this very useful, having found the need to fit some type of auto-couplings on my 4mm/P4 shunting plank, my eyesight no longer being up to the job of using 3-links.

 

As there was the requirement to retro-fit magnets into the track as electro-magnets were not an option, after some experimentation I have gone for the combination of 6mm x 6mm rod ones - they will just fit between the sleepers - and the 2mm mk3 S&W's.  I had these for my 2mm scale modelling before deciding DG's were better in this scale so thought I'd try using them in 4mm given the size issues with even the 3mm/4mm ones. With some alteration they enable quite close coupling and look slightly less obvious.  Having spent a modelling lifetime getting free running rolling stock the biggest challenge perhaps has been to make them the opposite so the S&W's work properly all the time, no random un-coupling when not wanted!  What fun......but worth it in the end.

 

 

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On 05/07/2010 at 12:57, Mikkel said:

Hi Will, glad it's been of use. The track-pin-in-plastic-block is the only method I use now, much quicker and less fiddly, I find.

Do you have a picture of the track pin method in use on a 4mm scale wagon ? I can't see the pictures in the older posts on here. I am also going to try the 2mm scale version to see if that is any better visually.

 

Many thanks

Rob

 

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Hi Rob, in the meantime I have shifted back to the original method. I found after a while that the track pin method was giving me unreliable coupling. I think the pins I was using may have been a smidgen too thick, causing the coupling to hesitate ever so slightly when moving. So I replaced them, and this below is how I've done all my wagons now:

 

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It's good that you raised it, I will edit my old post. 

 

The 2mm solution would look good, I'd be intersted to know how you get along with that. 

 

Edited by Mikkel
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To use the 2mm SW's for 4mm you need to make a few alterations. I can post a few shots of these, how I've done it, and what they look like, but wouldn't want to do that on your blog unless that is okay with you Mikkel.

 

Bob

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Quite a few modellers I understand use 3mm scale S&W's in 4mm, smaller and less obvious. When I decided I needed to fit some type of auto-coupling rather than carry on with 3-links my first thought was to get some. But as someone whose main scale these days is 2mm/2FS I already had some of the 2mm size ones I had tried before choosing D&G's as better for that scale.  So I thought I'd give them a go. But to do so meant making a few alterations.

 

Obviously as they are made to suit 2mm the hooks are a lot smaller so much finer wire needs to be used for the loops. I chose 0.3mm/30swg phosphor bronze simply because I had several coils of it. Mainly coming with the packs of 2mm DG's I get..... As the hooks are just 2mm deep there is far less leeway with differing loop heights so care is needed here.

 

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Since the hooks haven't enough length to work in 4mm with the pivot holes these need moving back by about 2mm. Drill new ones and then file away the excess in front of them.

 

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The pivot holes need to be at the headstock to get enough clearance over the buffer heads, so the hooks stick out far enough even with moving the pivot point back like this. The pivot loops are more of the PB wire. 0.3mm holes drilled into the headstocks into which they are pushed. How much lower than the underside of the headstock they are determines the height at which the leading edge of the hook rests. If the headstock is too thin then pad it out with plasticard at the rear before drilling. To give balance weight to the hook I add the etched fixture plate soldered onto the rear crossways. 

 

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As I wanted to try and just use small 6mm round magnets fitted in-between the sleepers I ditched ideas of using links and instead solder soft iron wire onto the hook and angle it forward so both are pulled down at the same time. 

 

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I also angle the hooks to one side  so they don't catch each other on curved track.

 

RMweb2mmSW08.jpg.583ef6ba60f99e7f0c05f4d5f92871ae.jpg

 

In use I have found that the fineness of the hooks etc. the small measure of leeway, tends to mean they can un-couple over fixed magnets when not wanted, so I would suggest that they need to be used only with electro magnets so this doesn't occur. 

 

I can't do this, fit these, the layout baseboard design won't allow it, so having removed the permanent magnets, and made magnet 'paddle sticks' ( from the old 3-link coupling hooks) using thin disc magnets to un-couple stock in the fiddle yard also now use this method on the layout itself. I just poke them under the couplings and the rolling stock can be moved apart while they are pulled down. 

 

RMweb2mmSW09.jpg.050c2494f3618290e6f7998ad6fbc4bc.jpg

 

Rather crude and simple, but easy to do. For a purely home based layout it's all I need, not much different to using 3-links but far, far easier!

 

Anyway, hope this is of help and interest. 

 

Bob

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Many thanks Bob.I have often been wondering about using 2mm S&Ws, so this is very informative. The hook certainly does look neater in a direct comparison.

 

I like those paddlesticks!

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Thanks Mikkel. Should add the magnets are glued on using Evostick for a bit of resilience. These thin type magnets can fracture quite easily under force and it usually stays a bit rubbery if put on thickly which you need to do to get a good fix on the brass wire rod. 
 

Bob

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