Screw Thread Gauge | Metric and SAE | Recommends Drill Bit & Tap Size (BCP675): Amazon.com: Industrial & Scientific
An easy to read chart of screw sizes and thread counts
Amazon.com: Ruelle Screw Chek'r SAE/ Inch Screw Thread Size Gauge (No. 1 to 5/16) 1/8 Inch Heavy Gauge Steel Screw Checker, Made in USA : Industrial & Scientific