I saw this post on the Artist Blacksmith Association of North America (ABANA) Facebook page. This is the design for a blacksmithing hammer designed to be shock absorbing and easier on the hands/arms. It splits the front third of the handle into twin handles and includes an oil-filled reservoir in the handle base. Both modifications are designed to decrease shock by increasing the impact flex and reducing vibration:
I thought starting blacksmiths (or those recovering from injury) might find it of interest and might even consider making one. For a cheap trial, one could use a Harbor Freight cross pein hammer’s head as a starting point, replacing the handle with a modified hickory one using this design.
$9 for the 3lb HF Cross Pein Hammer
$12 for a replacement handle from Amazon (assuming the original could not be reused).
Improving the Head While Improving the Handle
For tuning up the head itself, Alec Steele has a YouTube video on tweaks one can do to a cheap hammer to improve its performance. His tips mostly involve changes to the handle (which you’d be doing anyway) and using a grinder/sander to knock the edges off of the face. (Jump forward to 1:50 to skip the ad at the front.)