On Sat, 14 May 2005 12:26:15 -0400, Joseph Gwinn
wrote:

In article .com,
" wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.
[snip]

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

I would think that soft soldering would work perfectly, and is easily a
factor of ten stronger than any epoxy or loctite compound, so a soldered
connection will last forever in such service. So, I would suggest
figuring out why the soldering didn't "look good". Hand feeding the
solder may be the issue. Setting things up so that only the correct
amount of solder is used can help a great deal.

The standard trick is to pre-tin the steel using tinners flux (zinc
chloride in muriatic acid), wash the vestiges of the tinners flux off
with hot water, polish the hole in the brass with a rolled-up piece of
sandpaper or sandcloth, assemble, smear with plumbers grease flux, put
a small circle of solder wire right at the junction between steel shaft
and brass wheel, set up so it does not need to be touched or manipulated
while hot, and heat the wheel (not the rod) up with a large propane
torch. (Air acetylene would be OK, but oxy-anything is too intense.
That said, faster is better, as there will be less burn and scale to
clean up.) When the solder melts and flows, remove torch and allow it
all to cool. Clean off with solvent (to get the grease flux) and steel
wool (or the equivalent scotchbrite pad) used wet.

If necessary to get the tinned steel rod to fit into the hole, wipe
excess solder off the rod while it's still hot, using a damp paper towel.

Eutectic solder (63 tin, 37 lead) melts at 371 degrees C, the lowest,
and is very shiney. The tin-lead-silver solders are also very nice
looking, strong, and easy to use. In radio work, 2% silver is very
common, and easy to get. Likewise 63-37 eutectic solder.

Joe Gwinn

Adding to Joe's comments: I'd use a tin silver solder like Harris
Staybrite. Though a low temperature solder (430F), it's considerably
stronger than lead-tin solder and it's very fluid when it melts. No
need to pre-tin the rod, but I'd lightly countersink the flywheel on
both sides to provide a fillet area.