Bob from SWISCO responded:
May 8, 2019
Hi Paul. This pivot shoe looks closer to our 15-177. This shoe is compatible with our Series 152 Coil Springs. For the housing with the Series 152, we recommended individual housing for each spring: see our 15-143 bushing, the 15-144 bushing cap, and the 15-145 support barrel. As far as the spring weights you need, based on experience I think you're correct that the stamped letters might be converted to numbers, and that therefore you need an S152-7 (7 lbs of support) and S152-8 (8 lbs of support). To be safe, I'd weigh your window sash. If that exact weight is 30 lbs, dividing that weight in half would give you 15. That would mean you'd need 15 lbs of support on each side of the sash, which would confirm you need the S152-7 and S152-8 on each side of the sash. |
Tom from SWISCO responded:
May 14, 2019
We do have a coil balance with an explicitly longer leg, but it's not compatible with the 15-177 shoe. Our Series 152 should work for both the top and bottom coil spring. You just screw it to the shoe and pull it up. |