Junhasavasdikul had five birdies in his last seven holes and shot 6-under 65 and Crane had a bogey-free 7-under 64, putting them at 11-under 131 after 36 holes.
First-round leader Ricky Barnes shot 69 and is tied with Ryan Moore (68) for third at 10-under 132. Carl Pettersson (68) is in fifth at 9-under.
Crane started the day in a tie for 10th after a first round that included an eagle and two bogeys. He was much more consistent Friday, scattering seven birdies across his card. He had a birdie at the first hole, which he had bogeyed Thursday, and made the turn at 4-under. He added a birdie at 11 and moved into the lead with birdies at 15 and 17.
Junhasavasdikul was 1-under after 11 holes with bogeys at 4 and 11. But he ran off three consecutive birdies and, after a par at No. 15, had back-to-back birdies in getting to 6-under for the day.