On Thu, 26 Sep 2013 16:49:41 -0500, Pete Keillor wrote:

On Thu, 26 Sep 2013 15:13:52 -0500, Tim Wescott
wrote:

I'm working on a project (it's a visual pun -- because if you're going
to name an engine part after a body part, it should look like the body
part,
right?)

Basically I'm making a model airplane muffler (of a style called a
_tongue_ muffler, hence the near-obsessive search for a solution just to
make a god-damned PUN) by soldering two aluminum shells together (see
pictures). Later I'll solder the shells to a base that bolts to the
engine. If I just make one shell a little undersized compared to the
other and squeeze them together, I have a honkin' big seam that I'll
need to fill and file to get everything looking nice.

So I'd like to make a shell, then roll a little bead in it, then solder
everything together.

But I can't find any little bead rollers!!!

So, does anyone have any suggestions for what to do (other than perhaps
to abandon the project, or see a good shrink?) I'm thinking that for a
roller all I need are a pair of little wheels that are machined with the
correct 1/32" step, rounded to fit the interior of the shell, running on
bearings in a block and geared together.

Does that sound about right, or is there something I'm missing? I'd
like to make the amount of squeeze between the rollers at least somewhat
adjustable -- are there any known-good ways to do that, or is it
unnecessary?

Thanks in advance.

The pictures are he

https://docs.google.com/file/d/0B5lS...jajVqTWc/edit?
usp=sharing

https://docs.google.com/file/d/0B5lS...DcllvVWs/edit?
usp=sharing

I was thinking miniature tubing cutter with modified (blunt) cutter
wheel and grooved rollers, but it's probably too wide and no drive.

It'd be the wrong kind of bead, too -- I need more of a step.

I think I need to make something, but it astonishes me that there's not
something out there already.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com