A source of concentric brass tubes?

[Mathieu - Syvwlch]

If we could find ourselves a supply of concentric brass tubes, we
could try to assemble a clock based on those instead of bearings on
Saturday.

It might even be as simple as cannibalizing one of those collapsible
metal antennas? Although I think those have more slop than the brass
tubes I saw last time, and are much thinner walled.

We print the whole clock assuming the smallest tube's diameter for the
hub, and gently file the other gears' hubs as needed to make room for
the successively larger tubes... Or we print everything to size if we
have a good handle on the tube ODs.

For a full clock with minutes, hours, and a ratchet drum, we'd need
one for the core shaft (or some rod that fits the next tube snugly),
then one for all non-handed gears and the minute gear, then another
for the hour gear and ratchet to sit on.

Total three, or two plus a snug fitting rod inside the smallest.

[Mathieu Glachant]

Just to be clear, this can be used both for a separate shaft for the hands, or throughout e entire clock, replacing the bearings and eliminating the extra shaft.

[ruste...@prototribe.net]

McMaster is a great place for all sorts of hardware including brass 
tubing, but you'd have to wait for it to ship (do they have stores?)

http://www.mcmaster.com/

Tubing
http://www.mcmaster.com/#tubing/=g27ijb

Another possibility for the ball bearings may be teflon bushings cut 
from a length of tube.

[Mathieu Glachant]

Hum... I might be able to find metal and/or carbon tubes in a RC model store. We use them for wing spars and other structural uses...

[Tom Igoe]

Did you try smallparts.com?

t.