Ed,

A trick I use when reverse engineering (like you are doing) is to

consider that

the guy originally designing it probably had a relatively free hand at

selecting

dimensions so is likely to have selected even measurements where it

didn't

make any difference.   For instance - you measured the first radius as

3.95".

I'd bet that the drawing dimension is in millimeters, and 3.95 converts

to

100.33
... SNIP

Also, I think that certain items (o-rings included?) have been

stadardized on

mixed units because the US measurements were the first on the scene and
have not been replaced.  I think this is the case with o-rings having

inch

based cross sections as std (.0625 (1/16th), .125 (1/8th), etc) but

probably

mm for length (circumference) in metric countries.  FWIW.

Bill
Long EZ builder & pilot
mechanical engineer

Ed Anderson wrote:

Bill,
    You make a good point.  I should have converted the inch measurements to
mm to see what "round" number they were closest to.  Then it may have been
possible to find "O" rings in metric sizes.

Well, when I get this one in I will report how far off it is from fitting
and then try again.

Ed Anderson

 
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