Perhaps too weak windmill, try adding fifth sail set. Helve hammer takes a LOT of power. Not sure what the minimal requirement is, but from my experience by the looks of it it should work just fine.
Another idea i got is that perhaps the helve hammer requires rotation on the other side and gets stuck otherwise, though i'm not sure about it. Try changing the sides the helve hammer gets its power from and see if it works
Edit: definitely weak windmill, noticed you have increased power because of the large gear, and thus need FAR more input. To put it to perspective (in my numbers lol, not precise), 4 sets of sails windmill gives 80 power. Helve hammer needs 30. BUT the increase of speed needs 5.5x MORE power, which is 165, and the 80 power gain from the 4-sail windmill is too low