Stanley Extension Hex Awning Operators

Hi. I am desperately trying to find center operators for old awning windows. I believe they are called

Sorry, but I'm really not any kind of expert on window hardware. It doesn't look to me like the 39-076 would work. I've attached other pictures. There's a hole at the bottom of the window that you put the little bar (drive rod?) into. The bar has a 3/8 hex end and I don't know what you call the other end (spline?). The operator attaches over this. If I take off the operator as pictured, and use either pliers or the handle alone, the window opens and closes just fine, but that's not easy to do. It's the gears inside some of the operators that are slipping. Was hoping there would be some other operator that would fit over the 3/8 hex end sticking out in the picutre. Can't find this extension hex, or sometimes called angle adaptor, anywhere.