Hello,
The pictures attached are to a bottom sash replacement window approx 22 years old. The coil is a single coil 1/2 inch width. It only has one coil. It has a D stamped on the spring near the screw. I believe the mechanics are working fine.
I need two coils. And any advice you offer.
I am not sure what to order.
Both left and right bottom sash coils are broken

Quick Learner from Massachusetts
Aug 8, 2021 4:56 pm
5 user uploaded images
6 Replies

Emily from SWISCO
Aug 12, 2021 12:01 pm


Hello there!
Take a look at our 15-175 pivot shoe, which uses the Series 152 coil springs. Compare our dimensions to yours and see if this matches what you need.

Quick Learner from Massachusetts
Aug 12, 2021 2:12 pm
Thank you, I will check the dimensions when I get home but how do I know what weight the coil should be. The present coils are snapped in half. there is a "D" marking on the coil.

Emily from SWISCO
Aug 13, 2021 8:24 am


To determine your coil balance spring weight, you'll need to weigh your sash and then divide the sash weight by how many springs you have in the window.
For example, if you had four springs total (two on each side) and a 12 pound sash, you would want four 3 pound springs.
Let me know if this makes sense.

Quick Learner from Massachusetts
Aug 17, 2021 9:11 am
So I weighed the window to be 20 pounds. what would you suggest I get. I would assume I should replace everything and not just the coils. The old system had one coil on each side. I'll check the measurements again for the brackets that hold the coils. But your suggestions will help with my order.
Thank David
Thank David

Emily from SWISCO
Aug 17, 2021 9:47 am


In that case, two S152-5 coil springs on each side of the window should support your sash weight of 20 pounds.
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