|Second round leaderboard|
|-5 J Spieth (US), P Reed (US); -4 B Grace (SA), D Johnson (US)|
|Selected others: +2 L Westwood (Eng), J Rose (Eng), M Warren (Sco); +3 P Mickelson (US); +4 L Donald (Eng), R McIlroy (NI); +5 I Poulter (Eng), J Gunn (Sco), C Montgomerie (Sco)|
|Missed cut: +9 B Neil (Sco); +10 S Gallacher (Sco)|
Marc Warren remains the leading Scot at the US Open with his second-round 74 taking him to two over par.
Warren, 34, started day two on two under and shot six bogeys and two birdies as he went tied for 28th at Chambers Bay, seven off the lead.
Jimmy Gunn and Colin Montgomerie, both on five over, also made the weekend.
However, countrymen Bradley Neil and Stephen Gallacher missed the cut with amateur Neil nine over and Gallacher one shot further behind.
American duo Jordan Spieth and Patrick Reed lead on five under while Tiger Woods (16 over) was among those exiting before day three.
The third round begins shortly after 16:00 BST and Montgomerie will be second out with American Webb Simpson. Gunn is in the sixth group with Camilo Villegas of Colombia.
And Warren's round with American Kevin Na will start shortly before 20:00.