Billy Andrade, the self-proclaimed "bogey king", carded a three-under-par 68 to maintain a one-stroke at the halfway stage of the Pennsylvania Classic.
The American has enjoyed his week in the Philadelphia area, bogeying only one hole en route to a two-round total of eight-under 134 at the Waynesborough Country Club.
Andrade said: "You know, I'm obviously putting well, I'm making all of my short putts, I'm controlling my distance with my club selection, I'm not getting myself into too much trouble."
He began the day a stroke clear of two players and ended it one ahead of Canadian Ian Leggatt, who birdied five consecutive holes on the back nine and signed for a 65.
Kenneth Staton shot a 69 for third place at six under on 136.
Brent Geiberger, Donnie Hammond and Jeff Brehaut follow on 137, with Jim McGovern, Paul Goydos and JJ Henry at 138.
PA