ten little fingers - arvind gupta (4 mb pdf)

HANDPUMP1. For making this pump you willrequire a black film-reel bottle,one more cap, a cycle spoke,old cycle tube, an old refill,simple hand tools and Fevibond- a rubber adhesive.2. With a sharp scissors cut andremove the outer circle of thecap. The inner circle will make asuperb piston. Rub it a little onsandpaper so that it is free insidethe bottle - the cylinder.3. Make a 2-mm hole inthe centre and a 6-mm holefor the delivery valve port.Apply Fevibond to a 2-cmx 1-cm piece of bicyclerubber tube and stick it tocover the hole. This rubberwill act like a hinge andopen and close like a valve.4. Cut a 12-cm long piecefrom a bicycle spoke Fix thepiston on the spoke threadswith two nipple nuts.5. This is the piston, delivery valveand connecting rod assembly.6. Take another film-reelbottle cap and make a 6-mmhole in it. Apply Fevibond toa 2-cm x 1-cm piece of tuberubber and stick it on oneside to cover the hole. This isthe suction valve.7. Make a 3-mm hole inthe centre of the bottlebase so that the cyclespoke can move freelyin it. Make another holeon the curved surfacenear the base and fix anold refill or Frooti strawin it. This is the deliverypipe.8. Insert the spoke throughthe bottle base and snap thesuction valve lid to completethe hand pump assembly.Keep the pump in a bowl ofwater and move the spoke upand down. After a fewpriming strokes large quantaof water will gush out of thedelivery pipe with everyupward stroke of the spoke.Both the rubber washers -stuck only on one side ashinges, act as very efficientvalves. This is a superb modelto understand the working ofa real hand pump.