< 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".