* Futures down: Dow 53 pts, S&P 6.5 pts, Nasdaq 11.5 pts
By Chuck Mikolajczak
NEW YORK, Sept 9 (Reuters) - U.S. stock index futures were modestly lower on Friday amid investor caution following a nuclear test by North Korea and ahead of comments by two U.S. Federal Reserve speakers.
* North Korea conducted its fifth and biggest nuclear test on Friday and said it had mastered the ability to mount a warhead on a ballistic missile, drawing condemnation from the United States as well as China, Pyongyang's main ally.
* Investors will look for clues on the timing of an interest rate hike when Federal Reserve Bank of Boston President Eric Rosengren, a voting member of the Federal Open Market Committee, speaks at 8:15 a.m. EDT (1215 GMT). At 9:30 EDT, Federal Reserve Bank of Dallas President Robert Kaplan, a non-voting member, is also scheduled to speak.
* The Fed will hold a two-day policy meeting on Sept. 20-21. Expectations for a rate hike had climbed in recent weeks after comments from several Fed officials, only to be tamped down again in recent days after several disappointing economic reports. The current expectations for a September rate hike stand at 15 percent, according to CME's FedWatch tool.
* U.S. stocks have shown a lack of volatility for several months, with the benchmark S&P 500 index failing to register a move of more than 1 percent on a closing basis in either direction since July 8. The index is still only 0.4 percent away from its last record high registered on Aug. 15.
* Data due on Friday includes July wholesale inventories, which are not expected to have changed from the prior month.
* Also due is the weekly rig count from Baker Hughes, which could impact the price of oil after both Brent and U.S. prices surged more than 4 percent Thursday in the wake of a surprisingly huge drawdown in U.S. crude stocks.
* Restoration Hardware shares surged 11.1 percent to $39.19 in premarket trading after the company posted second-quarter earnings that topped Wall Street expectations.
* Samsung Electronics is considering selling its printer business to HP Inc in a deal worth around $1.8 billion as the South Korean company shifts focus to its core businesses, the Seoul Economic Daily reported.
* Pipeline company Enterprise Products Partners on Thursday withdrew its takeover bid for rival Williams Cos Inc , saying Williams' lack of engagement left it with "no actionable path forward."
Futures snapshot at 7:18 a.m. EDT:
* S&P 500 e-minis were down 6.5 points, or 0.3 percent, with 99,947 contracts changing hands.
* Nasdaq 100 e-minis were down 11.5 points, or 0.24 percent, in volume of 10,311 contracts.
* Dow e-minis were down 53 points, or 0.29 percent, with 10,700 contracts changing hands. (Reporting by Chuck Mikolajczak; Editing by Bernadette Baum)