What are most common spline sizes?

by Eric
(Colorado)

If I was to stock 2 or 3 of the most common sizes for window and door screens, what would they be?

0.160 and 0.180 round polyfoam are the most common sizes. It does depend on the types of windows and doors installed in your area. In Ontario, Canada where I live there are lots of old aluminum spline window frames that use 0.250 round polyfoam. Storm doors here use a lot of T spline.

In Colorado theres probably a few window manufacturers that have supplied home builders there for years and whatever spline sizes they used is what you are likely to need.