I only bought these to hold large sheets of plywood upright while I fastened the corners. They are perfect for that. I wasn't hoping for holding power or even accuracy, just a way to hold 4 sheets of plywood upright before twisting them together. Out of curiosity, I tried using them to glue the frame and it was a disaster. The pads fall off, the springs pop out, the plastic triangle slides everywhere. They are difficult to open but exert no clamping force. I didn't expect them to be good for this, so I'm not disappointed. Please note, however, that your mileage may deviate from this.