The Pump Drill is a further technical refinement of the hand drill and bow drill, and was used by the Iroquois. The pump drill consists of a wooden spindle, a wood or clay or stone fly wheel is attached to the spindle. A cross bar with a bigger hole goes onto the spindle above the flywheel with cord attached at each end which also attaches to the top of the spindle. The flywheel is wound up to wrap the cord around the spindle. The cross bar is then pumped up and down which makes the spindle spin into the hearth board. The weight of the flywheel produces momentum to keep the drill spinning. This method is supposed to create an ember much easily and quickly than the other methods. It was also used for drilling holes.
I thought I'd have a go at making one. This is the 3rd attempt - you do need to get the dimension rights and the flywheel needs to be heavy enough - mine is just under 500g It would probably be better using stone or clay. The most common advice is a 3:4:5 ratio for the triangle formed by the cross-bar (3), spindle (4) and string (5.) Mine is slightly taller on this one. My spindle is probably about 15mm in diameter. You want your spindle and cross bar at least 50mm in length, my spindle is a bit longer.
This was just a fun little experiment. It would be something fun to do with kids.