New post - replacement parts for spiral balance wood window

A home owner from USA says:

We have a series of older wood windows with spiral balances. While reglazing the window, we discovered that the spiral is bent. Attached are photos of the spiral spring balance with measurements. Which replacement part should we order?

If we find the right part - is it best to replace both balances on each side of the window - or just the one that is bent?

Also, the screw holding the spring balance in the top of the window has a different thread than we have ever seen. Do we need to continue to re-use this thread, or would a more traditional screw work with the replacement spiral balance?
User submitted photos of a window balance.
Profile picture of Tom
Tom from SWISCO responded:
I recommend looking at our Series 500 spiral balance. This is what is traditionally used in old wood windows like yours. You would also need a bracket like our 17-007. Check it out and see what you think.

I would recommend replacing balances on both side of the window. I'm not sure about the thread on the screw. The Series 500 uses our 33-016.
A quick learner from st paul says:
What is the screw you'd recommend for the bracket?
Profile picture of Paul
Paul from SWISCO responded:
For the bottom bracket, we recommend our 33-088 screw.
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