Hamfisted was used on another board recently (without the hyphen, BTW) and I had to look it up...there's only one hit on OneLook. It's a UKism, but there's also a USism mentioned as a synonym that I'm not really familiar with, though I think I've heard it once or twice along the way:

>from Cambridge Advanced Learner's Dictionary)

ham-fisted MAINLY UK adjective (US ham-handed)
doing things in an awkward or unskilled way when using the hands or dealing with people:
The report criticizes the ham-fisted way in which complaints were dealt with. <

Anybody use, or familiar with, either of the forms? Does the OED offer anything more?