< Emergency Hand Pump >
Although WILLIAM's drawings do not contain
the emergency hand pump, the casting set
from REEVES contains a hand pump body. I
designed my hand pump to utilize the casting.
The ram was made from free-cutting stainless
steel. The groove for O-ring was cut slightly
deeper than the standard, so as to reduce
friction. Tip of the ram is tapered to close
the bottom of the bore completely, in order
to prevent "air lock".
Gunmetal casting of pump body. The valve
chest at the left end is difficult to turn
in the lathe. Therefore I cut it out and
prepared new one from a round brass bar and
silver soldered onto the pump body.
Facing off the bottom at first.
Boring in the lathe to a close fit of the
ram. Finally the inner wall is horned with
a fine emery cloth to ensure smooth sliding
of O-ring. Also the outer surface was partly
turned (see the photo).
The operating lever is extended with a round
bar. The extension bar has oval hole which
was formed with a slotted round bar and a
cylinder glued together. The operating lever
section is turned from rectangle to oval
so as to fit to the hole.
The delivery valve seat was cut with a D-bit.
I recommend chromium-plated ball for the
seating and the vacuum test, although we
have to use stainless steel ball for practical
use.
The suction valve seat is as a nipple which
can be turned by normal knife tool and be
finished more precise than using D-bit.
Assembled hand pump. Each joint was secured
with a hardened silver steel pin and E-rings.
I recommend E-ring for such a hard-working
joint, because an E-ring has no chance to
loosen !
In the photo, the ram is at the back end
of stroke. Note the left edge of the operating
lever is hard up against the bottom of the
ram slot. This is as "back stopper".
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