Question about stamp on channel balance

Question

Hello, I am in the maintenance dept at a Florida FWC research facility. We are looking to do full sweep of channel balances at this facility. I have identified our series needed as "Series 390". Channels are 1/2" and bottom shoes are 1 1/8" deep. My question, is the stamp "1790" important or necessary for ordering replacements? For this specific 18" channel balance pictured, you do not have a "1790" stamp available. I have 15" channel balances stamped with "1490" and noticed that stamp is not available either. Any guidance would be much appreciated. Thank you, Jesse

Tom · Accepted Answer

Hello, Jesse. The stamp is extremely important, yes. That's what determines the calibration of the spring, the spring strength being the only reason a balance even exists.

Stamps ending in "90" use an old rating system that has fallen out of use in recent years. One of our standard options will likely work for you, but you need to weigh your sash to confirm which one to go with. You'll note that we have a chart on each balance store page that shows you how much weight each option supports. You simply need to weigh your sash on a scale and refer to that chart.