double hung spiral balancers, casement arms and cranks

Hello,

We can't be sure of what you need with the hardware still installed but you can start by comparing the specifications of the (3/8") S900 and (5/8") S600 spiral balances to yours. The primary difference between the two is the diameter of the housing tube. 

We also offer the 36-048 hinge set. Note that the base that attaches to the window sill measures 10" long and both hinges would need to be replaced. 

Unfortunately, we do not carry a replacement for the operator assembly shown in your first two photos. I'm sorry that we won't be able to assist with this part of your repair but please let us know if you have any other hardware questions. Thanks for posting.