Paul from SWISCO responded:
November 17, 2015
I believe what you are describing is something called an "invisible balance." This is when the sash is notched out at the sides to accept a balance that is screwed directly on. It also has a metal fitting at the end of the cord that is screwed to the jamb.
I have not personally worked with this type, as it is relatively uncommon. I'm sure you can understand why, since you're dealing with a hand-crafted window. For old wood sashes, I prefer using our Series 500 spiral balance with a metal bracket like our 17-012 (which would screw on the bottom of the sash). This method has been used for wood windows of all varieties since the 1940's, however you would have to continue the side notch completely to the top and bottom of the sash to accept the Series 500 balance. What do you think? |