Klauk established a new 36-hole record with his 10-under-par 134. Last year, three players were tied at 135.
Andy Bare (69) and Chad Ginn (65) are knotted in second place at minus-nine, followed by Matt Weibring, who shot a two-under 70 to come in fourth at eight- under 136.
Klauk parred his first four holes Friday, then hit a seven-iron to 30 feet and cashed in on the birdie opportunity. He played a 9-iron to eight feet to set up birdie at the eighth and made the turn at 10-under par for the championship.
Things fell apart a bit right away on the back nine for Klauk. He drove into the trees on the right side at 10 and could not save par. Klauk parred the next two, but holed a 10-footer for birdie at the 13th.
At the 228-yard, par-3 14th, Klauk knocked his tee ball into the left greenside bunker. He blasted out to 12 feet, but missed the par-saving putt.
Klauk recovered from the miscue at 14 one hole later. He hit a 9-iron to 10 feet to set up a birdie. That got him to 10-under par and it looked like he had one more great chance at birdie en route to the clubhouse.
Klauk's approach at the 17th stopped six feet from the stick, but his birdie try stayed above ground. He parred the last to establish a new 36-hole tournament record.
'I played well, just didn't hit as close,' said Klauk, referring to his 64 on Thursday. 'I didn't make as many putts. Days like yesterday make you keep coming back.'
Klauk has not won on the Nationwide Tour since the 2003 Wichita Open. He has a tie for second this year and a tie for fourth a few weeks back at the Henrico County Open.
'I've been in this position before,' acknowledged Klauk. 'It sounds boring, but you really have to stay one shot at a time and try to hit fairways and greens.'
David Hearn (69), John Kimbell (64) and Bryan DeCorso (69) share fifth place at minus-7.
Jeff Brehaut (65), Bill Lunde (68), Scott Gutschewski (70) and Ricky Barnes (63) are knotted in eighth place at 6-under 138.
The 36-hole cut fell at even-par 144 and Paul Claxton will not successfully defend his title. He shot a 2-over 74 and finished 36 holes at 3-over 147.