You need to replace a screw, but you just can’t tell whether it’s a 1/4″-28 or 1/4″-32. It’s an odd size, and you’d like to be sure so you can call around first rather than running all over town. Empire’s $14 screw ID gauge won’t just help you identify the screw, it’ll tell you the bit you’d use for tapping matching threads and the bit you’d need to drill a clearance hole.
Empire makes the 5-1/8″-long screw ID gauge from 5/64″-thick tempered steel. It’ll identify SAE standard screws and bolts from #1 to 5/16″, including their thread pitch. Besides screws and bolts, this gauge’ll also measure wire, pin, and rivet diameters.