Identify coil spring please

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Quick Learner from USA

Apr 5, 2017 8:11 am

Weight of bottom sash is approx. 25 lbs and the coil looks to have a marking of 35 on it.

User submitted photos of a window balance.

5 Replies

Paul from SWISCO

Apr 10, 2017 12:56 pm

I think this might be a match for our Series 160 coil spring. There should be another number aside from "35" printed on the spring but I can't make it out in your photo. It may be too faded. Check the other springs in the window to see if you can make something out.

Quick Learner from Weyers Cave, VA

Apr 10, 2017 2:02 pm

You are correct, it is too faded. I can try to look at others, but if that doesn't work, can I just order what you think I need to move this along please?

Quick Learner from Weyers Cave, VA

Apr 10, 2017 10:15 pm

I removed the other side and cannot read it. I have provided pictures of unnroken steel coil OD, steel thickness and width and dimensiom from slot to coil end. Steel slot width is 0.178 inch. The thickness of the steel is 0.015 inch.

Paul from SWISCO

Apr 11, 2017 1:55 pm

Well, what has me puzzled is that the window manufacturer only used two coil springs (one on each side) for a 25 pound sash. That would mean your springs are made to support 12.5 pounds each, which is exceptionally strong. We don't have any spring that large. If you are positive your sash is 25 pounds, I would recommend four S160-6 springs. Each of these can carry 6.5 pounds (26 pounds altogether, which we think should be okay), so you would use two on each side. I'd also recommend a double support like our 15-150D.