View single post by Herb Kephart
 Posted: Tue Nov 23rd, 2010 01:57 am
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Herb Kephart



Joined: Thu Jul 19th, 2007
Location: Glen Mills, Pennsylvania USA
Posts: 5981
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Ears, backbone and pulloffs


As posted before, I use the same wire for everything, but some modelers use a smaller gauge wire. For years I used the same beads as the “insulators” in the making of ears, but on occasion one of the beads would break at one point in the forming operation. It happened often enough that I determined on the present layout to look for something better. I went to Michaels to get insulator beads, and in the same area as the beads I found packets of small “gold” (brass) sleeves- pieces of tubing about 1/16” outside diameter by 1/16” long. Bought a couple packs and tried them, and they turned out to be much better than the glass beads as they don't break, and when soldering is done they become an integral part of the ear. Unfortunately, I haven't been able to find them on a couple return visits, and neither has a friend that saw me using them and wanted some for himself- and he frequents a different store.


Steps in making an ear
Cut a piece of wire about 4” long. 3/4” from one end, bend it back on itself (fig 1). The bend should be reasonably sharp, but the wires should splay out slightly from each other. Hang this piece over the span wire, or the lowest crossarm wire (fig 2). Slide the bead, or brass tube over both ends of the wire, and push it up as tight as possible against the horizontal span wire (fig 3) While holding the longer leg between the thumb and second finger, with index finger push the bead or tube up to hold it, and with pliers bend the short leg up to horizontal (fig 4) then cut it to 1/4” long. Next, bend the long leg horizontal, keeping it in line with the short leg in both planes (fig 5) Last, place the pliers at the 1/4” point on the long leg, and bend the excess up about 45* (fig 6) This is a “handle” that you can hold while soldering, and later trim off down at the trolley wire.






Backbone
This is nothing more than an additional piece of wire, strung from pole to pole around the outside of a curve. Its purpose is to have something to attach the short pulloff wires to. Backbone can be pieces of wire that go just from one pole to the next, or it can be a long length that makes two wraps around each pole that it comes to. Make the terminations of the wire ends to the poles, the same as shown for the span wire. Don't forget the insulators where the backbone comes up to the pole (about a scale foot away).


Pulloffs
Start out by making an ear, but in the process, put another piece of wire about 6” long where the span wire would normally go, loop it around the first bend in the ear wire and have the short end bent 90* to the long end and pointing down along with the long and short ear wire. (fig 7). Cut the short end of the pulloff so that it will just come even with the bottom of the bead or brass tube. Then continue the rest of the ear bending


Guy wires
These are wires that go from a pole, to an anchor buried in the ground, and typically they will be at about a 45* angle. They are most times on the outside of the poles around a curve, to keep the tension of the trolley wire from pulling the poles off vertical, and towards the track. Some of mine go through a hole in the tablework and are put under tension with a short, rather stiff spring. Unless the layout is located where the temperature and humidity are fairly constant, there will be times when the wire is slack, and others when the wire so tight that it may pull a few solder joints apart. I always had more trouble from the benchwork expanding when humid, and contracting when dry, than from temperature when I had layouts in a heated building- until I started painting all the major pieces of wood (including ply). After doing this most of my variations in wire tension went away- until the present layout. The first Winter the wire went more slack than I had ever had it go- so I took some of the slack out. The following Summer the wire got so tight that joints were being pulled apart left and right. I was tearing my hair out trying to keep up with all this, and wondering what the h##l was going on when I realized that the 40' aluminum trailer that the layout lives in expands and contracts close to 1/2” with the yearly outdoor temperature variations we have here, and the benchwork is bolted to the sides of the trailer.
This is why my guy wires are sprung. If a guy should need to come down in an impractical place- the middle of a road, or the bed of a creek for instance, put another pole on the other side of the road or stream. Connect the two poles with a horizontal wire near the pole tops, and then guy the second pole.


Two other items will be handy to have before we actually start hanging wire. One is a block of some material slightly less height than the intended wire. This should be a little wider than the rail gauge, 4-5 inches long and as heavy as possible- mine is steel, but most of you won't have a machine shop scrap bin to select a piece from. To the top of this fasten the largest ugliest paperclip that you can find- one of the kind with two ears that you squeeze between thumb and index finger to open. Fasten it to the top of the block, to grab the trolley wire and keep tension on it.


Second, an old, preferably unsprung, freight car truck, with a 1/2” square piece of wood fastened vertically with a screw through the kingpin hole. The top of this wooden piece should be the intended wire height.


Next time, we hang wire.

Herb  :old dude:



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