=>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.
HTH&GL
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.
Dan Mitchell
==========
Paul-News wrote:
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.
Dan Mitchell
==========
Paul-News wrote:
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