Spiral tube window

Thanks for reaching out to us, Ben. It looks like you have an old-style balance that I don't believe is made anymore. However, you could consider the Series 400. This is compatible with a handful of brackets but we commonly recommend the 17-031. See the options under the related items section of the balance product page to determine which options would fit best on your sash.

We also recommend weighing the window sash on a scale to determine the proper tip color option. We don't suggest guessing or estimates when it comes to the sash weight. 

Let us know if you have any questions!

In that case, you'd want the red tip color option. A pair of balances with this option will support a sash weighing 7 to 21 pounds. 

When you say your balance is 3/8" in diameter, are you referring to the tube or the spring? I believe the outer tube may measure 5/8". You want to measure the outer tube, not the spring, to determine the diameter. You could always double check to be sure.

Below are generic directions for the Series 500 which uses the 17-012 bracket, but you can try it on your Series 400 balances and 17-031 bracket to see if they work.

First, drop the balance behind the sash and screw the balance tube at the top of the track. Do the same on the other side. Raise the sash and have someone hold it up, while you place the 17-012 bracket under the sash and have it corral the spiral. Screw the bracket to the sash. Continue holding up the sash while you bring the spiral up to the bracket. Now turn the spiral clockwise with the 75-005 tool about four turns. Then lock the bow tie at the end of the spiral to the 17-012 bracket. Do the same on the other side and try the sash. If it creeps down, give the spiral another turn.