What coil balance do I need?

Thanks for posting. Your exact pivot shoe for this coil balance system is no longer made, but you should be able to replace it with our 15-177. This shoe, like your old one, uses Series 152 Coil Balances. If you're unsure of what spring weights to select, give us the exact weight of the window sash that these springs support, and I can work it out for you. 

Thanks! If your sash is 15 pounds then I suggest using our S152-4. These springs carry 4 pounds each, so having two on each side will add up to 16 pounds of support. That's a pound too strong but you won't notice the difference once they're installed. Just make sure to check the 15-177 dimensions to ensure that they all line up with the original. If they differ, let me know and we can work from there.

As for the lock, we sell several that are similar in design but this will also come down to size. Please measure the distance between the two installation holes and tell me what you get; make sure to measure from the center of each hole, not their edges. That will ensure the most accurate measurement. I can then check our stock for a good match.

Sure, using two 8 pound springs per side would be perfectly fine, if you'd prefer that. As long as they're symmetrical and as long as they carry the weight of the sash then you're good to go! 

Concerning the lock, with a hole spacing of 2-1/4", the closest option we have is our 90-180. Your next step should be to check the backset, which is the distance between the center of the holes and the glass-facing edge of the lock. The diagram below will show you what I mean; as long as your backset is the same at 3/8" then I'm very confident this lock will replace the original.

Dimensions for 90-180