From: A technical article on EG's site (emphasis mine):
http://www.eric-gorr.com/techarticles/2techcrankrepair.htm
The Right Special Tools
To rebuild a crankshaft, you need special tools. The two most important and expensive tools are a 30-ton hydraulic press (about $500) and a truing jig (about $750). It is possible to use a lathe as a truing jig but only when the crank is set between two live centers. You cannot clamp one side of the crank in the chuck and one end in the center and expect to get an accurate deflection measurement; the deflection of the crank is redirected, and the crank reads true when it is far out of true. Other
tools needed are a small square, a scribe, a dial indicator and stand,
a brass hammer, a steel wedge such as a chisel, and a variety of rectangular steel blocks and pins so you can secure the crank in the press during assembly. Mud Creek Engineering in Michigan (517) 676-9534 makes a great tool ($800) that allows you to assemble the crankshaft in perfect alignment; no additional truing is needed. The tool uses bushings to align the crank journals as the crank is pressed together...
and...
If the crank has side run-out, then the flyweights aren't parallel and must be adjusted before the crank ends can be trued. This is accomplished by
hitting the wide side of the flyweights with a large brass hammer...
and...
The crank ends have run-out because the flyweights aren't parallel and must be rotated about the crank pin. This is accomplished by striking the flyweight at the exact point of the greatest run-out, with a
brass hammer...
So, no...maybe you don't
install a crank with a hammer, but you sure use 'em in the process of rebuilding one.