Coiled Balance Spring

Question

Hi, one of spring was broken, but I couldn't find number near the nail. It's silver color. Could you tell it's 407 or 408. Thanks. Frank

User submitted photos of a window balance.

Tom · Accepted Answer

Thanks for posting! I cant vaguely make out a stamp in your first picture, though I'm not able to read it. That's fine, though. I can calculate what kind of option you should choose, I just need more information.

First, can you confirm how many springs you use on each side? I'm assuming you only have one on each side, but I just want to make sure.

Next, can you tell me the weight of your sash? You can determine this by removing the sash from the window and placing it on a scale. Thanks!