[SEL] More springs

Arnie Fero fero_ah at city-net.com
Wed Dec 7 07:16:37 PST 2005


Hi JB,

One alternative would be to use low-melting point alloys like Cerro-Indium
or Cerro-Bismuth.  They're commercially available and are used for fusable
links, fixturing parts for machining, etc.  They have melting points in
the range of 117-200 deg. F.  The disadvantage, as you've observed, is
that you need to make the forms.  At least removing the forms wouldn't
damage the springs and the material is reusable.  You might even find a
local machine shop that had some they would loan you.
One source is McMaster-Carr http://www.mcmaster.com/
Part number 8921K12.

As to cutting the grooves by hand, do you have any buddies with access to
a profile lathe?  That could solve that problem (once you've made a
master pattern).

You can also have fun with this stuff.  Cut the bowl off a spoon and use
the alloy to rejoin the two pieces.  Then give the trick spoon to a buddy
with a cup of "strong" coffee.  The natural reply to his shocked look when
his spoon "dissolves" is, "Gee, it usually doesn't take that long."

BTW JB, when you DO find out how they wound these barrel springs back in
1906, please let us know!!

See ya,  Arnie

Arnie Fero
Pittsburgh, PA
fero_ah at city-net.com

> Thanks Dave, ice doesn't last very long down here, wax and balsa would
> be too soft.  We have been discussing this locally, and lead and babbit
> were mentioned, but it would require making a new form each time, I want
> to do eight. Because of the barrel shape the guide threads will have to
> be cut while controlling the depth by hand, although not critical as in
> regular threads it would be time consuming to make eight. Then there's
> the possibility of softening the spring when heating to melt the form
> out. Just wondering how the factory did this in 1906.



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