Yes, PITSAW is a Scrabble word!

Letter values in Scrabble US: P 3, I 1, T 1, S 1, A 1, W 4.

Is it a valid word?

PITSAW is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a large two-handed saw formerly used to cut logs into planks; one man stood above the log and the other in a pit below