Bolts and Springs

These tools cover fasteners and springs. Get tightening torque and clamp force, bolt shear strength, the wrench size for a bolt, the rate of a compression spring and the torque of a torsion spring.

Tools in this group

• Bolt Grade Chart — Pick a grade and a bolt size to see its head marking, strengths, hardness and the proof and tensile load that bolt can carry.
• Bolt Head Size Chart (Bolt to Wrench Size) — Pick a bolt to get its wrench and hex key size, or enter a wrench size to see which bolts it fits and the nearest wrench in the other system.
• Bolt Shear Strength Calculator — Get the shear load a bolted joint carries from the bolt size, grade, number of bolts and shear planes, with an optional factor of safety.
• Bolt Torque Calculator — Enter the bolt size, grade and nut factor to get the tightening torque for a target preload, or the clamp force a given torque produces.
• Garage Door Spring Calculator (Torsion Spring) — Work out the torque per turn of a torsion spring and compare it with what your door's weight, height and drum size need.
• Spring Rate Calculator — Enter the wire diameter, outside diameter, coils and material to get the spring rate, and the load, deflection or stress for a given compression.