Window sash "balance" from the 50s?

Question

Hi, I pulled out two old single hung windows in my 1860s house. I have reason to believe the windows are from the 1950s (think knotty pine kitchen). I was surprised to see what was inside the two lower sash channels -- there's some sort of sash "balance" or sash stop? We don't think it helped to open the window, but just kept it from falling down maybe?  I'm looking to figure out how to modernize this or replace it. The spiral shaped metal rod has a clip that is screwed into exterior casing about 3/4th of the way up the bottom opening, but is otherwise not really attached to the casing in any other way. The metal rod is screwed into the sash channel end only and on the other side it is not attached and just floating there. There are no weights, ropes, strings, springs or anything that seems functional or offer counterbalance. The windows are kind of hard to open. I've googled this dilemma, but have come up empty. I'm hoping you've seen this type of window sash and can offer some recommendations? Thanks much.

Casey · Accepted Answer

For these old-style spiral balances with the spiral fixed to the mounting bracket, we like to recommend our 5/8" diameter Series 500 spiral balance and 17-012 bracket. These two parts together should act as a good replacement as long as the housing tube will fit the opening in your sash frame. First, you'll need to measure the housing tube, not including the spiral that extends from the bottom, to choose the correct replacement.

You'll also need to weigh the sash and follow the chart under the balance product description to choose the corresponding strength option. You may also want a charging tool like our 75-005 to help with installation. Take a look and thanks for posting.