If you normally work with inch fasteners, pitch can be a little confusing—pitch is the distance between adjacent threads. In the example above, a pitch of 1.0 means that from one thread to the next thread, the distance is 1.0 millimeter. Inch fasteners are described as threads per inch, which is sometimes mistakenly called pitch. Step 3 - Measure Length of Bolt. Since the length of the bolt is the last number in a metric measurement , you should measure for it last. Start from right below the head, including only the shank, and measure to the tip. This rule for bolt length holds true for most types, including cheese, hex, pan, socket, button, and low socket head types. M2.5 Screws . For instance if you are measuring an M2x5 pan head screw the overall length will be 6.60mm but it will be listed under the M2x5 because a pan head is measured from underneath the head where as a standard flat head screw takes its size from the measurement taken from top to bottom.

Metric bolts use the millimeter as the standard reporting unit. Measure the diameter of the bolt. Most bolts use the shank diameter , which is the distance from one side of the bolt to the other through the center, measured at the top of the bolt, just below the head. If you are searching for laptop screws be aware that some laptop manufacturers (ie HP Compaq) measure overall length but some measure from underneath the head like you would a regular pan head. If an herepaq manuals calls a 9mm length order an 8mm screw . Printable Tools for Measuring Fasteners . Printable US and Metric Ruler Print a fully functional US and Metric ruler to measure fastener length. Printable US and Metric Thread Gauge A printable paper version of our popular Thread Gauges. Use this tool to distinguish between coarse and fine thread bolts and machine screws , and between the many thread pitches used on metric bolts and machine screws .

Measuring Bolts and Screws . Flat head screws are measured from the top of the head to the tip of the threads. Oval head screws are measured from the beginning of the undercut on the head to the tip of the threads. Headless fasteners , such as socket set screws or dowel pins are measured … Other Considerations. You will need both the thread diameter and the thread pitch to determine the thread size. If you are measuring Imperial bolt thread size, you'll need to record the measurements as thread diameter followed by a hyphen, then the thread per inch measurement . For metric bold thread size, the formula is the thread diameter ,.