A cooper would use a flagging iron to insert reeds around the head of a barrel to tighten the head and stop any leaks. First the cooper removes the full and quarter metal hoops around the barrel, this loosens the staves and insert reeds around the head, prying the stave apart from the head with a flagging iron. Then he replaces the hoops to tighten the staves against the head and the inserted reeds to form a leakproof seal.
Significance
An age old tool used for many hundreds of years in the making and repairing of wooden barrels and an essential tool in a coopers tool kit.