I’m impressed a 2010 web page is still up. The links at the end are pretty much all dead. I have actually wondered what the angle should be when I turn a mallet—now I know.

They wrote about restoring a Ithaca model 37 last year. The post is also really good:

http://www.timberframe-tools.com/firearms/1975-ithaca-model-...

I've been surprised that no mallet manufacturer offers the purchaser the option of specifying the forearm length/desired angle for mallet heads.