34" tall x 1/2" U channel balance using string connecting to pivot shoe

Sure, this is a very common balance. I recommend our Series 770, in fact. I think you'll agree that this is a good match to your old hardware.

You really do your homework. Everything seems to check out, though I don't think the 15-188 is what you want in this case. The cam is a lot bigger than on your old pivot shoe and may not interact properly with your old pivot bar. Consider instead our 15-129. This looks like it might be a better match.

Concerning the strings, I'm afraid that's not something we sell. I don't believe any company does. These can be very difficult to replace since the balances are under a very precisely calibrated tension. I recommend just replacing the balances; it will be easier and your windows will function better for it.

Thanks for getting back to us! That pivot bar looks like our 26-368, but this isn't compatible with the 15-129. That is curious. Perhaps your shoe is different after all, though I'm not sure what else it could be. I personally think our 26-040 would be a better fit for your window. As long as it's one screw hole position matches up to your window then it should work well.

As for your stamp option being wrong to begin with, that's more common than you think. A lot of installers kind of just put in whatever they have on hand at the time, either because they're under a time crunch or, to put it bluntly, because they didn't know what they were doing. It happens all the time, unfortunately.

Please let me know if you had any questions.

If your sash is around 32 pounds then the 34D is definitely the right call. With 34C balances you may have noted that your windows are difficult to open over the years. Maybe it felt like it was stuck close, and maybe they even drifted down a little after you opened it. Those are all symptoms of a weak spring. Opening and closing a window with properly calibrated balances should be effortless. 

Hello! If your old pivot shoe is still in good condition then I highly recommend reusing it. That will likely make this pivot bar business a lot easier to deal with in the long run.

I can guarantee that the 26-083 can work with the 15-129, anyway. The 26-083 and 26-040 are pretty much the same part, the 26-083 just has different hole positions, which seem to match your original better anyway.