Review on Spring Clamps for Medium to Heavy-Duty Applications by James Nedumaran

I paint and when sketching in the first sketch I like to keep the canvas rolled up rather than stretcher bars. These clamps and others (so far) hold a 24" x 36" screen on aluminum poles without losing grip and with minimal play, even when the screen is held upright. 1-1/2", which allows me to use it with a thicker pole (and thus larger tarps), and the plastic grip on the handle provides ample grip with wet hands. The strength of this clamp, so expect some of either double them up or leave them in the toolbox (3 out of 15, after 1 month) Expect the plastic coating on the work end to peel off on first use (maybe stuck to your work) Bare metal is a U-shaped channel with square walls that goes all the way to the hinge and without the plastic coating it will ruin or scratch the work.As other people have posted there are ways around this problem.At the price of Sweet Clamp!