Paul from SWISCO responded:
May 26, 2016
We measure the length and diameter of the outer tube in order to determine the best match. We like to replace hardware with exactly what was in before, because that helps avoid complications, but in some cases there's a little wiggle room.
In your case, manufacturers used to make balances with lengths on the 1/2" all the time, but began to phase out that practice over the years. Most manufacturers like to make their balances on the inch these days. I think you could get away with our S600-27 spiral balance. This has an outer tube length of 27" and an outer tube diameter of 5/8". Measure your outer tube diameter and see if it's 5/8" or 9/16". If so, I think you'll be good with this. As for the metal tube, it won't affect the function of the window. We actually prefer metal tubes since they won't break apart when exposed to sunlight over the years. |