In a message dated 2008/08/20, paleoartifact@......... writes:

> The two separate masses weigh a total of 20 pounds. The absolute maximum 
> width of the spring allowed within the clamp is 0.311"; it could obviously 
> contain a smaller width ~ 0.25", for much easier insertion / replacement.
> 
> As a possible material prelude; I do have 0.007", and 0.014" thick phosphor 
> bronze shim roll stock.  I also have 0.010" thick blue tempered hardened 
> steel spring shim roll stock.  All old but never used.  All would need cutting 
> down and cut edge filing deburring to fit the flat clamp size firmly/easily; 
> all the spring widths are more than 0.311".  

Hi Meredith,

       OK. The spring is at about 45 degrees so the stress on the two strips 
will be about 20 lbs, say 10 lbs each. The tensile strength of bronze is about 
30,000 psi. Hence the absolute minimum strip thickness is about 1.2 thou. 
Allowing a safety factor of x10 gives 12 thou. 

       Looks like your 14 thou strip would probably do fine. 

       Note that you can buy hard rolled bronze weather strip for doors, but 
it is only about 6 thou thick. Hard rolled strip will have about 3x the UTS of 
the soft bronze quoted.

       Note that www.ksmetals.com stock 8 thou phosphor bronze sheet and 10 
and 18 thou SS strip.

       Regards,

       Chris   
In a me=
ssage dated 2008/08/20, paleoartifact@......... writes:



The two separate masses weigh a=
 total of 20 pounds. The absolute maximum width of the spring allowed within=
 the clamp is 0.311"; it could obviously contain a smaller width ~ 0.25", fo=
r much easier insertion / replacement.



As a possible material prelude; I do have 0.007", and 0.014" thick phosphor=20=
bronze shim roll stock.  I also have 0.010" thick blue tempered hardene=
d steel spring shim roll stock.  All old but never used.  All woul=
d need cutting down and cut edge filing deburring to fit the flat clamp size=
 firmly/easily; all the spring widths are more than 0.311".  



Hi Meredith,



       OK. The spring is at about 45 degrees s=
o the stress on the two strips will be about 20 lbs, say 10 lbs each. The te=
nsile strength of bronze is about 30,000 psi. Hence the absolute minimum str=
ip thickness is about 1.2 thou. Allowing a safety factor of x10 gives 12 tho=
u. 



       Looks like your 14 thou strip would pro=
bably do fine. 



       Note that you can buy hard rolled bronz=
e weather strip for doors, but it is only about 6 thou thick. Hard rolled st=
rip will have about 3x the UTS of the soft bronze quoted.



       Note that www.ksmetals.com stock 8 thou=
 phosphor bronze sheet and 10 and 18 thou SS strip.



       Regards,



       Chris