Fig. 2 illustrated a common solution to the problem.  This consists of altering the striker's swing so that his hands finish high enough to correct for the improper hammer face angle in Fig. 1.  This will work fine assuming you don't mind giving up a large part of the potential force which can be applied.  Hitting power can be figured simply by multiplying the weight of the projectile (hammer head) by the velocity upon impact.  Since the greatest acceleration is imparted in the latter part of the stroke, this technique is costly to hitting power.  Here's the important part:  double the weight of the hammer, or the velocity upon impact, and 1/2 the number of blows or less will do the same or greater work.  Double them both and accomplish the same work with 1/4 or fewer blows.  The import for lazy strikers such as myself is this:  refining technique and control of a weightier hammer and reduce the time and flailing on any given job.