What does the hammer symbolize in this story?

Toni Bambara's "Blues Ain't No Mockin Bird" is a story
whose subject is the exploitation of one group by another.  Like the chicken hawk, the
two cameramen are intrusive as they come onto the property without even saying "Good
morning."  They film what will serve their purposes, taking from the family what they
wish. Explaining this act of exploitation to the children, Granny likens their actions
to those of a cameraman who dispassionately flimed a person's
suicide,

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"Takin pictures of the man in his misery about to
jump, cause life so bad and people been messin with him so bad.  This person takin up
the whole roll of film
practically.... 

When
Grandaddy Cain returns from hunting a chicken hawk that has preyed upon their chickens,
he, too, is filmed by the cameraman.  Ignoring the men, however, he pauses by the porch
so that Granny can see that he has caught this hawk.  Then, he nails the bird to the
toolshed door, "the hammerin crackin through the eardrums."  As the pinioned bird flaps
its wings futilely, its blood runs down upon the gravel.  At this sight of the "tall and
silent and like a king" Granddaddy nailing the hawk, the two men move away from him. 
For, without saying a word, Grandaddy has symbolically expressed his disdain for the
exploiter.  Then, he looks at the men as though he has just noticed them; he holds out
his big hand, "a person in itself," until the cameraman gives him the movie camera. 
Granddaddy's bloody fingers curl up around the camera; then his other hand, like "a
sudden and gentle bird" hits the top of the camera, knocking off this half. Camera leaps
to save the film from exposure.  With no comment other than remarking that the men are
standing in his wife's flower bed, and "This is our own place," Grandaddy picks up the
hammer, returning it to his pocket, and goes into the house.  Cathy tells the narrator
that she is going to write a story about "the proper use of the
hammer."

This hammer represents the
protective power of the kinglike Grandaddy.  With the hammer, he ends the
predatory power of the chicken hawk that has been preying upon his chicken coop.  With
his powerful hands, he ends the predatory filming of their family and property, so he
does not need to use the hammer, but it is there if he needs it.  Like the gun that is a
deterrent for cowboy, the hammer is returned to his oilskin pocket as it has
symbolically spoken to the two men.