I have a number of the same size windows where the operators seem to have a lot of play in them especially when its windy and are also very loose in their open/close operation. I assume that over the 40 years they have been in that the metal gears have become worn.
Based on the way you show your measurements for new ones, mine are as follows.
Screw to screw distance = 3"
Arm length - 13 5/8"
Mine have two screw holes unlike yours that show a third one in the middle of each side.
The only markings are on the bottom as 42 LH
The total width of the base is 4"w x 2 3/4"d and 5/8" high at the center of the base. The manufacturer of the window is unknown
I will need both left and right ones in the same color.
