Abstract: An aluminum window frame construction which includes: an outer frame having a header, a sill and first and second jambs. At least one sash frame assembly is mounted in the outer frame, including a top portion, a bottom portion and first and second side portions. The frame is formed with radiused corners to enhance strength and such that a sight-line of about 2¾ inches is created at a top of the window frame construction when the top portion of the sash frame assembly is positioned in abutment with the header. A sight-line of about 3⅜ inches is created at a bottom of the window frame construction when the bottom portion of the sash frame assembly is positioned in abutment with the sill, and a sight-line of about 2⅜ inches to about 2¾ inches is created on at least one side of the window frame construction when one of the first and second side portions of the sash frame assembly is positioned in abutment with one of the first and second jambs.