Tensioning Helix-Sprung Windows

My house was built in 1982. All windows are metal with moveable lower sashes and fixed upper sashes. On each side of the sash is a tension mechanism consisting of a spring inside a cylinder and a spiral metal band attached to the spring at one end and to the bottom of the window at the other. The other end of the cylinder is attached to the upper part of the window frame with a screw.

I can remove and reinstall the window, but I don't know the technique of pretensioning the spring so it will hold the window in any open position. If I twist the helix enough for adequate pretension, then I can't pull the pin at the end of the helix far enough to catch it in the grove at the bottom of the window.

So, how does one reinstall and pretension this type of sash without having the thing slip and taking off a finger in the process?

 

There are special tools that have 2 little hooks at the end, and the handle has 2 90 degree angles in it. You reach into the channel, grab the hooks, and unhook it from the balance shoe. Using the tool you can put a couple extra turns on the balance to increase the tension, and then slip the end back into the balance shoe.

Now -- where to get one of these? When I worked for a window manufacturer, our machine shop made them for us. I found this one at Home Depot, and it looks right, but I don't know if the hooks will be right for your balances.

http://www.homedepot.com/prel80/HDUS...e=12-5577377-2

 

Helluva tip!! That was certainly helpful info. I was able to d/l the company's window catalog and saw some stuff I had been looking for for a long time!!! Thanks!!