Tell One Screw From Another

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.
Screw ID Gauge [Empire Level]
Via Amazon [What’s This?]
I have both an inch and a metric version and they are great for figuring which type the small screws are.
I do too Chris! And I used to have a big box of loose screws that are now cataloged by size and stored in plastic bins. It was a nice rainy day project and no more trips to the store to buy one screw.
I like the Screw Chek’r brand, made of heavy gauge satin chrome plated steel with precision machined threads.
Those flat metal ones don’t have enough thickness to it to tell one from the other and it only does screws and bolt not nuts.
I prefer this one from http://www.mcmaster.com carr part number 20375A21
And if you need not just the commen metric and SAE sizes the have more extended versions http://cgi.ebay.com/ebaymotors/Nut-Bolt-Thread-Checker-METRIC-Size-Gauge-Tool_W0QQitemZ120111464931QQcmdZViewItem