'going at it hammer and tongs'

[mindbullets]

any ideas where this originates

[Bert]

This is really just a guess, but I've always thought the expression was to do with a blacksmith, holding a piece of hot iron with tongs and hammering it vigorously, making the sparks fly.

[Quizmonster]

Click http://www.worldwidewords.org/qa/qa-ham1.htm for confirmation of Bert's earlier "guess".