Help Identifying An Old Channel lock

Question

Hi - thanks so much for offering to identify this for me. The window is from about 1975 and has never been worked on.
The length of the channel is 21". The width of the channel is 1/2"
The Channel balance fitting depth: 1.08" (27.7 mm)

I saw your article about some fittings with pulley wheels needing to be a special order - is that what's going on with mine?

Thanks again for your help!

Mindy

Emily · Accepted Answer

Hi there Mindy!

Thanks for reaching out to us. No, this balance doesn't have to be a custom order from what I see here. You have either the S351-21 or S390-21 with the 2030 stamp option. The difference between the two Series is the depth of the bottom shoe as shown below.

I wonder if your shoe was once 1-1/8" but wore down over time, though we cannot be sure. Take a look at the specifications for these parts and let us know if you have any questions.

Comparison of the S351 and S390 balance shoes.