A 5/8 inch bolt come in two different thread pitches. The pitch of the threads will determine how the bolt behave when under a load. The thread pitch will impact how the bolt reacts to vibrations, and the thread pitch will determine if the bolt remain in place over long periods of time.
Use the chart provided to determine the two standard thread pitches for an 5/8 inch bolt. The chart will provide the numbers for drilling, torquing, and purchasing the correct bolt. The selection of the thread pitch allow for the engineering component to be determined, rather than guessed at.
5/8 Inch Bolt Threads and How to Use the Chart
Bolts come with coarse thread and fine threads. Coarse threads will cut deeper into the material than fine threads, allowing for faster seating of the bolt. Coarse threads is used for the connections of structural steel component and heavy equipment frames.
Fine threads will leave more material than coarse threads at the root of the bolt. Because there is more material at the root of fine threads, fine threads can provide higher tensile strength to the bolt of the same 5/8 inch diameter. Fine threads are also useful for allowing components to be adjusted to precise specification.
The chart will display both coarse and fine thread for comparison. The values for torque for dry bolts will be listed on the chart. These values is for dry bolts only.
When lubricant are used on bolts, such as anti-seize compound or cutting oils, the lubricant will reduce the friction on the bolt. Because the lubricant reduces friction, the bolts will generate more clamp force with less effort by the mechanic using the wrench. Using the dry torque value on a lubricated bolt will create more tension on the bolt than should be applied.
The tension can stretch the bolt to past it’s proof load. Therefore, adjustments need to be made if lubricant are used with the bolt. This is one of the reason for the use of wet torque values and dry torque values.
The tap drill size are selected based off the material in which the bolt will be used. The tap drill sizes indicated on the chart will create approximately 75% of the threads engaged with the materials. This percentage is use as a standard recommendation.
Softer metal will allow for a smaller drill bit than castings that are brittle. Using a larger drill bit will require less torque to be exert when tapping the hole into the materials. The fractional and decimal size will be provided on the chart for ease of understanding.
The size of the bolts hexagon is important when purchasing the tool for the bolt. The across flats measurement will allow for the purchase of the correct sized wrench for the bolt. The across corners measurement will ensure that the bolt will clear any obstruction with its head.
These two measurement will be provided on the chart. For example, a 15/16 inch socket may be required for the across flats measurement, however a 1 inch open end wrench may not be able to fit into the across corners measurement. Additionally, impact socket should not be used on these high strength bolts; ordinary chrome wrenches may shatter when used in impact application.
A 5/8 inch bolt is the same size as an M16 bolt. However, the pitch of the threads and the size of the wrenches that are used with these two type of bolts does not match. It is not advised to force a 5/8 inch bolt into an M16 bolt hole, as this will damage the threads.
Additionally, using either the imperial or metric system will damage the equipment. The rules for thread engagement are based on the materials that the bolt is tapped into. Steel require less depth for the threads than aluminum require.
This is because steel can carry more load per thread than aluminum. Steel is a more stronger metal than aluminum. The minimum depth for 5/8 inch bolts are provided on the chart to avoid calculations when using the drill press.
The thread pitch can be determined in the field. Coarse threads and fine threads can be distinguish by running a fingernail across the threads. The thread count can be determined by counting the number of threads over one inch of the bolt.
The markings on the bolt head indicate the grade of the bolt. The grade of the nut should match the grade of the bolt. Using a nut of a lower grade may result in the nut stripping under the tension of the bolts of a higher grade.
Use the chart to determine the type of thread pitch that should be used, the size of the drill bit, the torque that should be used when tightening the bolt to the component, and the size of the wrench that will be used. By making these four determination based on the chart, the mechanic can avoid any surprises during the installation of the bolt.
