Rodger Davis posted his second round of 4-under 67 in as many days and is alone in third at 8-under par. Gil Morgan and Tom Watson share fourth place at minus-7 after matching rounds of 66.
Quigley flew out of the gates Saturday with a 15-foot birdie putt at the first. He followed with a pair of 10-foot birdies at the third and fourth holes to move up the leaderboard.
'The big difference today was I made some early putts,' said Quigley, who shot an opening-round, 3-under-par 68. 'We all hit it pretty much the same. The difference is whoever is holing the putts.'
Quigley added a seven-foot birdie putt on No. 8 to make the turn at 4-under 31. He continued his fine play at the start of his second nine. Quigley reached the green in two at the par-5 10th, but his eagle putt missed just short. He tapped in for birdie and holed a 12-footer for birdie at the next hole to leap into a share of the lead.
The 55-year-old parred the next five holes before the 17th, when he knocked his approach to five feet. Quigley failed to convert that birdie try, but sank an eight-footer at the last to take sole possession of first place.
'All in all it was just a good round of golf,' said Quigley, who won this year's Siebel Classic in March. 'Saturday is an important day. If you can have a good round you can pass a lot of people.'
Quigley is competing in his 200th consecutive event that he has been eligible for, a streak that dates back to August of 1997.
'I'm proud of my streak,' said Quigley, a six-time winner on the Senior Tour. 'There is nothing I enjoy more than playing a round of golf.'
Fernandez slowly reached second place as he was only 1-under on his round through 14 holes. He converted a five-foot birdie putt at the 15th and closed with a 15-footer and a five-footer at the last two holes to get within one of Quigley.
'Overall I struck the ball steadier than yesterday,' said Fernandez. 'The swing felt better as well. I felt I was in better control of the ball today.'
Fuzzy Zoeller, the 2002 Senior PGA Championship winner, is alone in sixth place at 6-under par. George Archer, the overnight leader, struggled to a 2-over 73 Saturday, and is tied for seventh with Bruce Fleisher and Tom Kite. The trio stands at 5-under-par 137.
Full-field scores from the SBC Championship