WASHINGTON, July 27 (Reuters) - New orders for key U.S.-made capital goods increased solidly in June despite supply constraints hampering production at some factories, suggesting business spending on equipment could remain strong beyond the second quarter. Orders for non-defense capital goods excluding aircraft, a closely watched proxy for business spending plans, rose 0.5% last month, the Commerce Department said on Tuesday. These so-called core capital goods orders gained 0.5% in May. Economists polled by Reuters had forecast core capital goods orders advancing 0.7%. (Reporting by Lucia Mutikani; Editing by Andrea Ricci) Our Standards: The Thomson Reuters Trust Principles.