Thomas George Stiles original back spectacle ACL version.
Showing at least the lens pocket diameter is in fact 2 7/8
again these things can be ordered with larger or even smaller size diameter lenses but generally 2 7/8 has been seen as the norm for Stiles mechanical dwarfs.
My first mechanical i received later, a cast copy back spectacle, which i should at the time, think of measuring that back spectacle pocket on first chance to help the one popular question of signal collectors
in regards to shrinkage .
to even get a three inch lens (FSO) in that back spectacle which the purple lens had a horrible seam rim on the edge i ground that lens under three inches and opening up the pocket of the re cast spectacle and unfortunately because of my lack of proper tools had to do the work by hand so i cant say how much material was lost in making the pocket near three inches .
Its does seem from many in the collecting field, say re cast of originals parts shrink by 1/8.
Thomas George Stiles original back spectacle ACL version.
Showing at least the lens pocket diameter is in fact 2 7/8
again these things can be ordered with larger or even smaller size diameter lenses but generally 2 7/8 has been seen as the norm for Stiles mechanical dwarfs.
My first mechanical i received later, a cast copy back spectacle, which i should at the time, think of measuring that back spectacle pocket on first chance to help the one popular question of signal collectors
in regards to shrinkage .
to even get a three inch lens (FSO) in that back spectacle which the purple lens had a horrible seam rim on the edge i ground that lens under three inches and opening up the pocket of the re cast spectacle and unfortunately because of my lack of proper tools had to do the work by hand so i cant say how much material was lost in making the pocket near three inches .
Its does seem from many in the collecting field, say re cast of originals parts shrink by 1/8.