AN ILLUSTRATED GUIDE TO ASSEMBLING D.G. COUPLINGS
By Steve Bennett
One of the problems facing every narrow gauge modeller at some time is in choosing which coupling to use, as there is no standard to work from and a multitude of choices. This piece is intended to assist others who may wish to follow a similar route to my own and hopefully pass on some constructional tips that I have learned along the way.
D.G. Couplings are now produced by Model Signal Engineering and at long last are available online from : http://www.wizardmodels.co.uk/FrameSetS ... M=wizabout
I have been using these couplings for over ten years in various sizes and in several scales and gauges, so when it came to choosing an automatic coupling for use in Gn15, they were the obvious choice for me. The sizes I have chosen are designed for O gauge and are described as the Type C coupling. In addition to the couplings, they are also able to supply a jig for bending the loops, which I would recommend as a worthwhile purchase as it aids construction considerably, this you will see further on. The beauty of this system is that it gives completely hands free coupling and uncoupling and also features a delayed action facility. Unlike many magnetic systems, there is no necessity to stop over a magnet in order to uncouple, this can be done, while pushing a wagon, with a slow speed pass over the magnet.
Although well designed there are a couple of things that you ought to be made aware of. The first is that they are a fiddly to put together. This is not to say they are difficult, it is just that the parts are quite small in size, which makes them difficult to handle. The other problem is with the instruction sheets that come with them, which are very thorough, but overcomplicated and the drawings are a little confusing. In addition, unless you intend to turn your wagons or locomotives on your layout, a loop is only needed on one end, not on both as described in the instructions, cutting down on the work involved and improving reliability. Another plus with my methods, is that you don’t need a soldering iron at all, just basic hand tools, that most modellers will already have on the bench. I do apologise for the quality of the photographs used here, I’m afraid my camera has real difficulty focusing on items this small.
Well enough of my rambling lets get started.
In the picture above you will see the etch of sixteen couplings as they come from the pack. In the centre are the main body of the couplers and along the edges are the latches for the delayed action facility. I find it best to remove one coupling from the etch at a time to avoid loosing any parts. Using a sharp craft knife (don’t use a brand new blade) on a firm surface such as a cutting mat, cut through the nibs that hold the coupling in the fret, as close to the part as possible. Then take a fine file and clean up the remainder of these nibs. Now take the main part of the coupler and bend the buffing plate at a right angle along the fold line, using either a pair of tweezers or a pair of smooth jawed pliers, as in the picture below. The instructions that come with the couplings say to add a fillet of solder to the inside of the bend, this is totally unnecessary and prevents any fine tuning if needed later.
Bending down the buffing plate will automatically raise the coupling hook, bend this back at a slight angle, about 20 degrees from the vertical, this allows the loop from the adjoining coupling to rise up over the hook. Next bend down the loop brackets, on the sides, so they are at right angles to the main body of the coupler. Your coupler should now look like the photo below.
Now for the fiddly bit, the delayed action latch, which is lot more difficult to describe, than it is to do. This part is only needed if you want to make use of the delayed action facility. If you are going to just uncouple over a magnet this is not required. Cut away the delayed action latch from the fret, again as close as possible to the part. As the latch is so small, it is best placed in a pin vice to hold it to clean up the nibs. Still using a pin vice, insert the latch with the fork uppermost as in the photo below.
Now place the main body of the coupler over the fork on the latch as per the photo.
Then insert the blade of a knife between the two forks on the latch, which will spread them slightly. This is all that is required to hold it in place. It should now look like this and pivot easily back and forth.
Using a pair of tweezers gently bend the latch into a curve as shown in the photos below. When the coupling is held level the latch should rest on top of the coupling hook under its own weight, if not adjust the bend.
That is the main part of the coupling complete, now we move onto making and fitting the loops. You can follow the instructions that come with the couplings and using the wire supplied but there are, in my opinion, better and simpler ways of doing this.
If you follow the instructions supplied, you will need at least three hands to hold the bits while you solder a steel dropper onto a phosphor bronze loop to create the coupling loop. A far better way which is both easier to do and more reliable in operation, is to bend the loop and dropper, in one go from a single piece of soft steel wire. The wire I use is intended for flower arranging and very easily worked. If you cannot find a source locally, then scenic modelling specialists, Greenscenes, sell the same thing for use in making armatures for model trees. You will find that a jig is pretty essential for getting a uniform loop and it does aid greatly in bending the wire to shape. The jig sold with the couplings is a worthwhile purchase (it is also useful for grab handles) but it is fairly simple to make your own, all you need is a block with dimensions of 7.5mm by 5mm to wind the wire around. In effect, using the soft wire, you form the loop by bending it around the jig, then doing a final tidy up with either pliers or tweezers. This is a lot easier to show than to describe, hopefully this photo will illustrate how it is done.
The dropper on the loop is left over length at this stage, only trimming it back so that it just clears the rails, once installed on the wagon. To fit the loop onto the coupling, the soft wire makes it easy to open it out to allow the pivot to be threaded onto the coupling body, squeezing back to the correct shape again afterwards. Minor alterations to the shape are easily done with a pair of tweezers.
Finally, for finishing off, a chemical blackening is recommended, but an alternative is to spray very lightly with matt black aerosol paint. This works fine if lightly applied, but you may need to clear a little of the paint once dry, from around the pivot of the little delayed action latch on top of the coupler, in order to let it move freely.
That really is about all there is to it. Although at first glance these couplings look really difficult to put together, after you have done a couple, you will see how simple they are. I wouldn’t recommend doing a whole load of them in one sitting, better a few at a time, but once you get a feel for them, you will wonder why you hesitated in the first place and will be rewarded with one of the best automated couplers available.
A short piece on fitment from another thread. More to come :