Hurd window crank

Thanks for reaching out to us. We're happy to help with this, but we'll need more information. Can you open the window and show us a clear view of the arms that move the window sash? 

Thank you! Take a look at the 39-253LB & 39-253RB along with the 39-438B & 39-439B operators. The important difference between them is the design of the guide used, which is explained in the video below. Review the specifications and see how they compare with your old assembly.

Note that the 39-451 and 39-452 covers/handles are sold separately. 

Please let us know if you have any questions.