G&J Headstocks

[Andrew Aspland]

On the subject of G&J headstocks - Birstall (1919) have hollow-section CI
headstocks which look very much like the Taylor ones - as do the H castings
for the frame. When did they develop the web-section ones? Certainly by
the 1930s they used them exclusively.
Birstall have the most odd stay and slider mechanism - a plain stay with the
"slider being a wooden roller about 6" dia running in a quadrant "cage" -
the problem is the wooden roller wears on the rusty metal cage and tends to
stick as well as making the bell deeeper set. Any more out there?
Andrew