My channel balance is stamped 1640 and measures 17" metal to metal. Do I measure the shoe straight across (like the measuring tape shows in the photo) or do I follow the curve which would make the measurement longer? Also regarding the photo of the metal piece- do you carry these? They were smartly placed inside the balance top to add strength to the plastic:)
Thanks Alot!
Hello,
It looks like you have either our S351-17, with a 15-002 bottom attachment, or S390-17, with a 15-001 bottom attachment. Take a look at the image below, which shows exactly how to measure the shoe, to determine which balance you'll need. You'll also need a 1640 spring strength option for your replacement balances.
Also, our balances do not use a metal piece like the part in your last photo but it would help to see a photo of the part installed in the balance.
As for your top sash guides, take a look and compare the dimensions shown on the 18-107 product page to yours. Thank you!
![How to Replace a Top Sash Guide [1080p]](../../images/videoThumbnails/107.jpg)
