Disclosed is an a mountable leveling support clamp comprising a mounting
plate, a support arm having a horizontal and vertical portion
incorporating a leveling indicator and threaded throughbore with an
adjusting screw having a locking plate on one end and a handle on the
other. The support clamp is designed to temporarily fix the positioning
of a horizontal member to an upright as permanent fasteners are applied
thereto, whereupon the support clamp is removed.