Page 7 - RD_2019-09

Left: The two most unusual features of the H & H
are the efficient drum shutter that cuts the light
beam simultaneously from top and bottom giving
better light transmission than the usual segment
shutter; and the 8-frame intermittent sprocket
system instead of the usual cam and claw move-
ment. Also, the canvas Bakelite gate pressure
plate on the right was less likely to cause scratch-
ing on the emulsion side of the film than the usual
steel pressure plate.
The aluminium body castings are painted with
crackle finish gray and all the exposed bear-
ings have a high quality chrome finish. The
other steel parts and fittings have a blue/gray
gunmetal finish, all of which combine to give
the projector a solid professional look even
after some years of obvious neglect. The main
gear train runs in an oil bath and has not the
slightest sign of wear, in spite of the gate and
film sprocket teeth showing signs of heavy
usage.
The unique
features in-
clude an 8
frame intermittent sprocket movement instead of the usual cam
and claw mechanism used on 16mm projectors. 35mm projec-
tors have a 4 frame intermittent sprocket driven by a 4 sided
maltese cross, a 4 frame sprocket in 16mm would be too small
for practical operation, so an 8 frame sprocket is required to get
sufficient film wraparound. This means an 8 sided maltese
cross is needed to drive it. While not as efficient as the 4 sided
cross due to the smaller cam faces involved, the system works
very well on the Harmour
and Heath. The teeth on the
16mm intermittent sprock-
et must also be milled (cut) Above: The long hardened steel
with perfect precision to aperture plate (the rear half of the
obtain a rock steady picture gate) shows little sign of wear and
on the screen. An efficient two pairs of lateral guide rollers
drum shutter is used in- ensure perfect film stability.
stead of the normal vertical
segment type. Revolving at one revolution per frame the
narrow drum blades cut the light beam from the top and
bottom simultaneously, giving a smoother transition from
picture to picture. This higher efficiency eliminates the need

Left: The exciter lamp is the 10 volt 7.5 amp type normally used in
35mm projectors of the 1940s vintage. Like every other working
part on the machine the assembly is readily adjustable.

REEL DEALS September 2019 7