swage block

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A metal block with holes or grooves for shaping metal objects.

from The Century Dictionary.

• noun A heavy block of iron, perforated with holes of different sizes and shapes, and variously grooved on the sides: used for heading bolts, and swaging objects of larger size than can be worked on an anvil in the ordinary way.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an iron block cut with holes and grooves to assist in cold working metal