The corner vice holds pieces up to 3 1/4 inches thick, tightly and at a perfect right angle for welding or machining. Bolt it down to your work bench, drill press, or mill, or just use it as a portable clamp for smaller jobs. The heavy cast iron construction makes it strong and stable, even when not bolted down, but it’s not so heavy you can’t move it around the shop, or take it to the job site with you. The opening where the jaws come together means you can clamp T shaped joints too. The clamping jaw swivels and self-centers, it is free to move and hold 2 different thicknesses of material together. The threads on the screw spindle are copper plated to keep them clean and free of welding slag mishaps, for years of use.