Model Forum / General / Models / April 2008

I had always wondered what I can use the Dollar Store battery (double
AA) powered item ID etcher/marker for.  This is a solder pen-like tool
with a tiny bur bit on the end. My first impression was that it
vibrates like the much more expensive and much heavier marker tool
that works off the wall socket.  But 2 cells provide only 3 volts and
there is certainly not enough power for a vibrator let alone have an
electromagnet and dc to ac circuitry to generate the vibrations.

So I took one apart and the guts was a small dc motor that had a thick
rubber tube/cylinder to hold the bit to the motor shaft.  So it is a
rotary tool. A Dremel drill can do the same thing except it is too
fast and will melt the plastic on any speed setting.  The dollar tool
is very light and comfortable for precision manipulation and the speed
just right for cutting into styrene.

For better performance and save on batteries I would have to connect
it to a 3 volt or 4.5 volt power cube transformer. In trying to solder
the 4.5v cube transformer to the motor and metal switch tab the
plastic tongue holding the tab broke and there was not enough plastic
to remelt the tongue.  For a buck it was cheaper to buy another tool
than spend time on heroic repairs.  This time round don't even mother
to expose the motor.  Just solder the transformer to the center brass
eyelet where the battery anode would press against.  There is a metal
ring inside the handle barrel for the cathode.  Solder the other
transformer wire to this ring.  To make a strain relief for the
transformer wire tie a knot in the wire so that you cannot pull it out
of the barrel.  Works like a charm so far.  It makes a clean groove
and will require multiple passes to cut deeper.  I'll probably use a
Xacto knife to deepen the cuts as a faster way but haven't got around
to doing a real project yet.  But I can see this as a darn useful and
very cheap too that will have plenty of other applcations.

My "It's a good solution" application was finally the need to make a
clean precision cut into styrene with a minimal kerf.  I want to
convert the Tamiya early production 1/25 Tiger I cylindrical turret to
a mid production Tiger with cast turret.  Carving the cast turret or
making a vacuumformed one is too much work and complication. I got
from eBay a (amateurish) built Academy 1/25 Panther aufs A that needed
rework to provide the cast turret.  I will use the Tamiya early Tiger
cylindrical turret to backdate the ebay Panther to the early aufs D.
I already have both 1/25 Tiger and Panther models built out of the
box, thus the attraction of making the conversions.