A block (a wood or metal unit containing one or more pulleys) and tackle (an assembly of blocks and ropes) permits multiplication of force to lift or move heavy objects. This amazingly simple device - a prime tool of ancient builders - remains extraordinarily useful in the modern world.
Obtain a standing block and a traveling block, each incorporating a single pulley.
Choose blocks with hooks so that you can attach them to a support and to the load. The standing block will be attached to a support and, thus, needs two hooks (or attachment points). The traveling block will be attached to the load and requires only one hook (or attachment point).
Identify whether the block pulleys are made for rope or for wire cable.
Find strong rope or cable that fits the pulley and is, at a minimum, three times the distance you plan to hoist.
Suspend the double hook block (block A) from a support, remembering that the support must be able to withstand the weight of the load and its movement.
Attach the traveling hook block (block B) to the object being lifted, such as a bucket.
Stand at an angle to the double hook block so that you'll be able to move the rope freely.
Draw the rope through the pulleys to take up slack.
Pull slowly and steadily with the lifting rope until the object is at the desired height.
Tie off the end of the lifting rope to a permanent object before unhooking the load.
Lay out the blocks on a clean, dry surface. You must keep the pulleys free of dirt, debris and moisture.
Secure the end of the lifting rope to the bottom of the standing block.
Thread the lifting rope around the bottom of the traveling block and back up and over the top of the standing block.
Your rope must be free of knots or frays so that the pulley wheels spin easily and the rope fits securely in the guide track. Use a belay while lifting or lowering for extra safety. A belay is a solid, anchored object that you can pull the rope around to allow you to rest between pulls. Wear gloves when pulling on ropes or cables. Keep others away from the block and tackle when it is in use or when it is supporting a load.