The trouble with the design of this blast gate is there is no way to clean out any accumulated dust.  Even with the best dust collector, you will always get some stray dust or debris that accumulates on the gate.  Every time you open and close the gate, this dust get packed into the bottom of the gate.  Eventually, the gate will not close all the way.  As more dust gets trapped, the less the gate can close.  I didn't observe this until about a year after using them.  I will have to replace all these gates with the metal version which has cut corners that will not allow any dust to get trapped.  With the metal version, any dust or debris gets pushed out of the corners when the gate is closed.