=>Are there any mfg's that make HO Scale 4 wheel tender trucks with all-wheel =>electrical pickup? I'd like to replace a set of trucks on an old tender =>that I own. =>
=>If not, where can I find some plans on making one myself? =>
=>Thanks, =>Paul =>
=>
No plans, but a brief description of what to do:
a) make a T-shaped spring-brass or spring bronze pickup ; the crossbar will bear on the insulated wheel sets.
b) drill a hole through the bolster of th truck, and use an insulated bushing (Footnorte) plus nut and bolt to fasten the pickup in place. Bend and file until the pickup works as desired. You may also have to file the bolt flush with the nut so it doesn't catch on the underside of the tender.
c) sodler a length of very flexible wire to a suitable size washer. Fasten the washer under the bolt.
d) drill a hole through teh tender floor for the wire to pass through. This hole must be big enough so that the wire has plenty of room and doesn't bind.
e) run the connection from the wire to wherever it needs to go.
Footnote: insulated bushing is available from Kadee and other sources, or make your own with a bit of plastic tubing, eg spent ballpoint ink tube, and plastic washers.
I don't know of any 4-wheel (or 6-wheel) trucks with all wheel electrical-pick-up on the market.
Depending on your skills, they're not too hard to make from most trucks having metal wheels.
I start with a small chip (perhaps 3/8" sq.) of thin (1/32") circuit board (CB) material (glass epoxy is especially good, but phenolic will do fine). Size the chip to fit on the truck bolster, but not rub on the wheels. PLAN on how to fasten the CB chip to the bolster. Every type truck is likely to be different.
Do not attach the CB yet. Eventually, the CB may be screwed (00-90 or
0-80 machine screws) to the bolster, or attached with epoxy glue, depending on the truck. If you choose to screw it to the bolster (best solution), make sure you don't short the foils through the screws. This is not a problem if the bolster is plastic. You can also use plastic screws, or countersink the metal screws into holes in the CB so the screw heads do not touch the foils.
The CB chip may be mounted to either the top or bottom of the bolster. The top is probably better, if there's room for it. The bottom works 'OK' too, but clearance over the track may be a problem.
Cut a channel through the copper foil, dividing the CB metal foil (only) into two electrically isolated sections (right and left, on the truck, one side for each rail). This groove may be cut with a hobby knife, small chisel, or with a cut-off disk in a motor tool. Check the cut foils with an ohmmeter to make SURE they are separated (microscopic shards of the cut copper may still short the foils together). Do not excessively weaken the base material of the CB.
Solder two thin metal 'wipers' to each of the CB foils (or one double-ended 'wiper'), rubbing on either the top tread or backs of the wheels (depending on the truck) on each side. For the 'wipers', phosphor-bronze (available from Clover-House, and specialty metal suppliers) is the preferred metal for the 'wipers'. It is hard and springy, and solders easily. Hard springy brass will work if you can't find PhB. Take the extra time to solder TINY 'shoes' (perhaps 1/16" sq.?) of nickel-silver metal to the rubbing tips of the 'wipers'. These provide superior electrical contact, and can be easily replaced when worn down (they WILL wear down).
Side note: Lots of brass model locos use thin wire wipers for electrical pick up. These wear down wonderfully fast, eventually degrading loco performance. It's worth the time to add such pick-up shoes to the wipers before you run the loco a lot.
Solder two very flexible pick-up wires to the CB foils, one to each foil. It is worthwhile to use a 'strain relief' where the wires solder to the boards. A tiny piece of small brass tubing soldered to the foils works well ... pass the wire through the tube, then solder in to the foil. Another was is to drill a small hole through the CB, passed the wire through the hole from the back side of the board, then solder to the foil. A drop of epoxy will also work to hold the wire. The idea is to force the wire to flex somewhere INSIDE the insulation sleeve, NOT at the point where the conductor is soldered.
NOW, fasten the circuit board to the truck bolster. Adjust the wipers to make LIGHT contact, minimizing friction. They WILL create a 'drag', but it need not be extreme.
Connect the other ends of the wire to the 'load' (motor, lights, whatever).
The improvement in electrical pick up can be dramatic. I use the technique on many tender, caboose, and passenger car trucks.
Most any electronic supply (All Electronics, Newark, Digi-Key, Mouser, even Radio Shack) will have this material. Many surplus dealers also have CB material. Sometimes you can get a useable small 'chip' off the corner of a junk CB from some electronics apparatus (you often only need pieces less than a half inch square). Try a TV repair shop (not very many left around anymore) for junk pieces.
To cut it, the easiest method is to use a small fine-toothed hack saw. It's abrasive and will soon wreck the saw if you cut a lot of it, but the blades are cheap. You can also score it and 'snap' it (sometimes, depending on the type of board). It can sometimes be cut with heavy duty shears, but, again, it will wreck the tool if you do it often. A cut-off disk in a hand "motor tool" is also a good way.
The cut off chip can be shaped and sized with a file. The CB material can be drilled and tapped easily, but, again, it will wear and dull the cutting tools, so don't use your best tools for this purpose.
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