Window crank handle. no markings

Thanks for posting. I believe this might be an operator from an old "Ulaco" operator. I don't think they are still available. I am afraid I don't know what you could replace the handles with, or the complete operator. If you want, you can show us a picture of the complete operator out of the window from a bird's eye view, including the link arm(s). We'll then do our best to find a potential match. Otherwise, I'm afraid it's possible you'll need a new complete window. 

Thank you! I definitely think replacing the complete operator is your best solution. Take a look at the newer style 39-410 and 39-411. These may be your best bet. Look over our dimensions and let me know if you agree.