I'm about to replace my patio door screen using fiberglass screen,
I bought a three sizes in one package.
Is there a proper way to measure the groove to know what is the right size rubber spline to use.
The spline should fit into the groove under pressure excerted by a spline roller. You definately need this tool to properly do the job. The spline should be tight enough that you can't get it in there with fingers alone.