Re: GunFest 2002

[Frank Pittelli <frank-at-pittelli.com>]

In Reply To Doug Smith Who Wrote On 16 Feb:
>
> Frank,  I loved your tank.  I am trying to make some 1/12 scale tanks but
> can not for the life of me work out a track system that doesn't cost more
> than the tank.  How did you do your tracks?

Here's the formula for a cheap, yet effective, tank track:

1) Acquire some surplus chain (we don't want to know how or where it
was acquired ;-)  For larger scale tracks, bicycle chains work great
and are readily available.  (Will bought some old bikes at auction for
about $1 each, just to get the chains!!!)  For smaller scale tracks,
get smaller chain (take-outs from office machines, etc).  You'll need
two chains for each track.

2) Cut plywood/aluminum/steel slats that are as long as the track is
wide and as wide as the links are long.  (E.g. Since bicycle chains are
1" on center, the slats should be 1" wide).  You can make the slats a
little narrower if you want to account for sloppy drilling in step #3. 
You can also mold track slats out of a resin of your choice if you
prefer a more scale look, but good ole plywood is the cheapest solution
and is very durable with a coat of epoxy to seal it.

3) Set up a jig and drill two holes in each slat, exactly in the middle
lengthwise and equally spaced from each end.

4) Rivet each slat to each chain using the appropriate size rivet for
the size of chain being used.  For bicycle chains, 1/8" rivets are
perfect. My original tracks were pop-riveted with the rivet going
through the chain and then through the slat, leaving the end-nub
protruding on the outside of the track.  That provides some extra
traction (like studs in a snow tire) but that may be good or bad
depending on how your tank handles terrain and steering.  For my next
tracts, I may reverse the direction of the rivet (probably requiring a
washer on the inside to prevent the chain link from being forced open)
or may use rivets that are hammered flat instead of pop-rivets.

5) After the tracks are made, make drive wheels that fit inside of the
two chains.  Mine are covered with rubber to provide more traction
against the track.  Friction drive appears to work well enough, even
for tanks weighing over 50lbs. The chains are used to hold the track
together and to prevent the track from slipping off of the drive
wheels.  We used to use bicycle sprockets to actually drive the track
via the chains, but they always came off in rough terrain.    

> The smaller blowgun paintballs give a better scale to the models though you
> have to make your own guns.  

Yep.  We have a prototype breach for a 40cal paintball gun and will be
developing that further after the 68cal gun is working.  (68cal is
scale for my Tiger, so you can imagine why it moved up on the priority
list.)

        Frank P.