Now freeze the transformation [Modify-Freeze Transormation]
now select the object and click the edge loop tool and create four edges like the image show below
Now create a Cylinder Primitives and adjust it like the image show you
And select it vertexs and adjust it like the image
Again click on edge loop tool and create the edge and adjust it
Create a cube and adjust it like the image
And modify it like the image show you below
Now again create cube and adjust it like image
And open up the attribute editor and adjust its setting Subdivisions Width - 6
Subdivisions Height - 6
Subdivisions Depth - 6 And now select the vertex with right click and adjust the vertexs like the image below
Now mirror this object By clicking Mesh-Mirror Geometry settings
Now adjust its Mirror direction to –y
Now you get that kind of an object
And now your hammer is aproxmetly complete
Now just select all the object one by one and modify it poly to subd [Modify-Convert-Poly To Subd]