Thanks for posting. We may have a handle that fits that bore, but it depends on its diameter. Is it 3/8", or more like 11/32"? That will narrow down your options. However, I should stress that if you can open the window, but it won't close, this is typically a sign that the entire operator mechanism has broken down and should be replaced. You have an older style Andersen operator which is no longer available. We believe our 39-365 might work as a substitute, though it may take some adaptation to work. You could use an under-sash track like our 39-504 or the face mounted track like our 39-520 . I'm afraid I cannot guarantee that any of these will work, since yours is so old, but we do not have a better option. Take a look and let me know what you think.
I'm sorry to say I can't determine the hole diameter based on this photo. The tape measure you're using is unfortunately not quite as accurate as it needs to be. As mentioned above, a common option is 11/32", so you will need a measuring implement that allows you to cover that at minimum.
As for what to measure, all you're measuring is the diameter of the hole. Once you have that, you should be able to pick the best option.
