Three-link couplings for 4mm scale

[Jeff Smith]

The Hornby screw couplings look good but are a bit tight for practical use.

[Captain Kernow]

19 hours ago, amdaley said:

What is the minimum radius most 3 link couplings will take ?

Cheer.

Tony.

I've had them working OK down to something just over 2 foot radius.

 

[amdaley]

8 minutes ago, Captain Kernow said:

I've had them working OK down to something just over 2 foot radius.

 

What brand were you using ?

[Captain Kernow]

Just now, amdaley said:

What brand were you using ?

Smiths, most of the links were of the normal (slightly larger) size.

 

Most of the hooks are not sprung and most of my OO stock does not have sprung buffers.

 

[The Johnster]

You can get them working down to about 2’ radius with the cheat of extending the hooks half a mm further out from the buffer beam than they should be, which is not noticeable.  
 

If you have permanently or semi-permanently coupled rakes that can be left on the layout, it’s worth checking out ‘James’ Trains’ on Shapeways; these are 3D printed couplings designed to ‘plug’ into NEM pockets at both ends on adjoining vehicles.  A ‘dummy’ hanging coupling is included on one end, and details include the ‘horns’ on the centre link of instanters that enable shunters to shorten or lengthen the coupling with a shunting pole without going ‘in between’.  3-link, instanter, and screw are available, but instanters are printed in the ‘short’ position.  They will prevent buffer lock on curves down to 24” radius, including when propelling.  A drawback is that they are a little brittle if twisted, so care must be taken when you are disconnecting vehicles, and they have to be painted. 
 

No connection satisfied customer.  I used them at one time when I was running full and empty rakes of permanently coupled minerals, but now I have built the colliery everything needs to be capable of being shunted, so I’ve ‘reverted’ to normal couplings, NEM tension locks in my case because my eyesight and hand/eye co-ordination is no longer up to using scale couplings in my dotage.  I’ve been experimenting with home made hook and loop couplings to enable more reliable propelling, but care in track laying makes this unnecessary, if you can persuade all your tension lock bars to sit at the same height above the rail!

[CloggyDog]

My preference is for Smiths links* and Ambis hooks, also Ambis instanter links where required. 

 

The Ambis hooks have a finer appearance over Smiths hooks.

 

*Ambis also sell packs of the Smiths links. 

 

The combo works fine for me under exhibition conditions (Shirebeck, EM gauge) on a wide range of kit and rtr stock. I use the standard links and wield a simple hooked shunting pole, having never got on with magnetic links. 

 

 

[Peter Kazmierczak]

Thanks again for all your comments; most helpful. My local model shop (luckily I still have one) was out of stock before Christmas, so I've just put in an online order for some Smiths 3-link (LP1) and instanter (LP2) couplings.

 

I'll let you know how I get on.

[Peter Kazmierczak]

So, I ordered the couplings on Boxing Day and they arrived in the post this morning (30th). Pretty good going I think.

 

After assembling one you have to:

• Question your sanity
• Have a strong torch to find the split pin which (however careful one is) will "ping off somewhere
• Wonder if tension lock couplings aren't that bad after all
   

I'll post some photos tomorrow. Off to lie down for a bit now...

[SM42]

My method with the split pin is to hold the spring back against the rear of the buffer beam with a pair of tweezers, gripping the hook tail and then slip the pin in the hole (using a pair of  fine long nose pliers to hold it.) 

 

Once the pin is in, the spring can be gently released and the pin can then be split with a knife blade being forced in between the pin legs. 

 

Andy

Edited December 31, 2022 by SM42

[Captain Kernow]

Or, don't use the spring and split pin set up at all and just glue it in.

 

[MartinWales]

13 hours ago, Peter Kazmierczak said:

So, I ordered the couplings on Boxing Day and they arrived in the post this morning (30th). Pretty good going I think.

 

After assembling one you have to:

• Question your sanity
• Have a strong torch to find the split pin which (however careful one is) will "ping off somewhere
• Wonder if tension lock couplings aren't that bad after all
   

I'll post some photos tomorrow. Off to lie down for a bit now...

Once you've assembled some-you will become more proficient!

 

Trust me! I remember demonstrating assembly at the Nottingham show whilst operating too (but very slowly shunting!) 

[Peter Kazmierczak]

Here's the wagon for the first fitment. An old Airfix GW Toad I picked-up for under a fiver. As it's only a bit of GW tat, it doesn't matter if I make a hash...🤪

 

 

[PMP]

Like @Captain Kernowi too don’t bother with the springs on any of mine. Many years of practical experience in both EM and OO shows it to be a waste of time for no real benefit. On RTR in particular you’ll find that the wagon weight will be so long it fouls the shank and spring of the coupling. The quick fix is cut the shank short rather than the wagon weights. Fix the coupling with low viscosity super glue from behind the bufferbeam. 

[Peter Kazmierczak]

First step being to remove the tension-lock coupling and its mounting. I removed the wheels and van body so I could better attack the plastic. This takes the longest time to do. I used a variety of tools; a small saw, craft knives and files. Be careful to not accidentally (like me) cut-off some of the sideframe detail...🤔

 

 

Edited December 31, 2022 by Peter Kazmierczak

[Peter Kazmierczak]

Next step is to drill a couple of small holes in the bufferbeam - I just used the finest drill I had between my fingers - and make it into a small slot. Then I pushed the hook shank through, slipped on the spring and fixed with the split pin. The actual hooks were probably the easiest bit to do.

[Peter Kazmierczak]

Is it worth it? As others have mentioned above, I can't see much point in the springing arrangement. But I wanted to fix one using a spring just to show that I could. Maybe a dab of Araldite in future, rather than messing with springs.

Edited December 31, 2022 by Peter Kazmierczak

[Barclay]

I stopped using springs, as I found that when there was a reasonable load the couplings of the lead wagon would pull out to their maximum length, which looked wrong of course. I'm sure there's a happy medium, where they don't do that but still have the flexibility to help on curves etc. I just never bothered to look for it !

[jwealleans]

I have to say that the springs I've had with mine are too strong to pull out much if at all unless something has actually jammed in the track.   I use them because it makes the couplings easily removable if you need to fit something else (Kadees for shunting on Grantham, e.g.).

 

If you carry on with them, Peter, you'll find that after a few wagons where you have to shorten, bend and glue (or solder) them, you'll accumulate a surplus of split pins and springs.   I only buy hooks and links these days and am working my way through the bags of the rest I've gathered up.

Edited December 31, 2022 by jwealleans

[Peter Kazmierczak]

Think I'm getting into the swing of things with these now. This is an old  Mainline wagon. Having watched some folks on YouTube fitting three-links, I'm surprised many don't remove the big plastic coupling mount - seems to be a key thing to cut off.

 

Anyway, as this is an unfitted wagon, I also removed the moulded vacuum brake cylinder from the underframe. Not sure whether to cut down the weight, as it's too large to fit now, or model the wagon loaded with coal and hence slip the weight under the load.

 

Oh, and a Happy New Year to you all!

[Captain Kernow]

Hi Peter, that's looking good!

 

For what it's worth, I've described my method of fitting Smiths 3-link couplings in this thread concerning the conversion of a Rapido wagon to P4 - 

 

 

[Peter Kazmierczak]

Very interesting, Cap'n; though I don't plan to venture into the dark arts of P4... 🤪

 

Just a quick question. Did many (most?)  wagons have that tiebar in the centre of the wagon joining the V-hangers?

[Captain Kernow]

2 hours ago, Peter Kazmierczak said:

Very interesting, Cap'n; though I don't plan to venture into the dark arts of P4... 🤪

 

Just a quick question. Did many (most?)  wagons have that tiebar in the centre of the wagon joining the V-hangers?

As far as I know, it's not a tie bar, but an integral part of the brakes, so that if you have brake shoes on one side only (as per this prototype), then this bar carries the actuation of the far-side brake lever to the brake mechanism.

 

[Peter Kazmierczak]

Thanks. Methinks I'll need to mug-up on my underframes...

[Barry Ten]

Another vote for the basic Smiths type. I only spring them when I'm putting them in bogie stock. Even then, I cut the spring in half, roughly, and then re-extend it until it's about the same length as before. This seems to give enough slackness for the springing effect to work. Out of the bag, they're far too stiff to have any practical value.

 

Other than that, I almost always glue them in and I've found most wagons can be safely propelled through the diverging route

of a Peco double slip, which I think is around 2 foot radius. Very occasionally there'll be a troublesome truck that needs a bit of extra attention, such as eliminating as much play between the axles and axleboxes as possible, but by and large 3 links are quite tolerant of tight radii.

 

 

 

[jwealleans]

1 hour ago, Captain Kernow said:

As far as I know, it's not a tie bar, but an integral part of the brakes, so that if you have brake shoes on one side only (as per this prototype), then this bar carries the actuation of the far-side brake lever to the brake mechanism.

 

Peter, are you referring to the tie bar between axleguards on fitted wagons with only 4 brake shoes?   That's to prevent the action of the brakes from forcing the axles apart.

 

If you mean the shaft between the brake levers then as Tim correctly observes, it's to allow the brakes to be operated from either side of the wagon.  This became a requirement around the time of WW 1 as far as I recall.