SCREW THREAD CALCULATORS

Screw Thread Calculators given in the following chart are categorized as Metric threads, Unified threads , Acme threads, Buttress threads and Pipe threads. Screw thread calculators can be used for the calculations of different screw parameters such as tap drill sizes, thread size calculations with tolerances, bolt torque calculation, etc.

Screw threads which are widely used in the world are Unified threads, ISO metric threads, NPT pipe threads, Acme threads and Buttress threads. ISO, Unified and NPT Pipe threads have same thread profile and the profile is V shape with 60 ° angle.  Acme threads have trapezoidal thread form with 29°. Buttress threads have load angle of 7 degrees and a clearance angle of 45 deg.



CALCULATORS
Calculator Usage
UNIFIED INCH SCREW THREADS
Clearance Holes For Bolts, Screws and Studs (Inch) Calculates the recommended clearance hole sizes from #0 through 1.5 in for bolts, screws and studs in three classes of clearance using close-, normal- and loose-fit category.
Tap Drill Sizes Calculates recommended cutting tap hole size limits and appropriate tap drill size.
Counterbore Sizes for Socket Head Cap Screws Calculates the recommended clearance hole sizes from #0 through 2 inches for socket head cap screws in two classes of clearance using close- and normal-fit category. The recommended inch drill bit size for each class of clearance hole is shown in calculation results.
Roll Tap Drill Sizes Calculates recommended hole size  before cold forming tap and appropriate tap drill size.
Bolt Torque Calculator Calculates estimated required bolt tightening torque, minimum length of engagement to prevent stripping of threads and dimensional properties of fasteners such as shear area of external and internal thread and tensile stress area of bolt. The calculator can be used for Unified inch screws threads in the size range from ¼ in to 1 ½ in and covers standard series of UNC, UNF and UNEF
Unified Inch Screw Thread Sizes & Tolerances Calculator Calculates basic major, minor and pitch diameters of the external (bolt) and internal (nut) inch thread according to ASME B1.1-2003 standard. In addition to basic size calculations, limits of sizes calculations of different tolerance classes can be done according to same standard.
Helicoil Insert Length Selection Calculates the helicoil insert length selection to develop the full load value of the bolt rather than stripping the tapped material.
Helicoil Screw Thread Insert (STI) Tapped Hole Dimensions Calculates helicoil tapped hole dimensions.
ISO METRIC SCREW THREADS
Bolted Joint Calculator Roughly calculates bolt diameter according to basic joint parameters.
Clearance Holes For Bolts, Screws and Studs (metric) Calculates the recommended clearance hole sizes from M1.6 through M64 mm for bolts, screws and studs in three classes of clearance using close-, normal- and loose-fit category.
Counterbore Sizes for Metric Socket Head Cap Screws Calculates the recommended clearance hole sizes from M1.6 through M48 for metric socket head cap screws in two classes of clearance using close- and normal-fit category. The recommended metric drill bit size for each class of clearance hole is shown in calculation results.
Metric Bolt Grades and Strength Calculator Shows proof strength, tensile strength, minimum breaking torques and stress area of metric bolts and screws made of carbon steel and alloy steel.
Metric Bolt Torque Values Calculator Shows bolt torque values and assembly preloads permitted for metric bolts and screws made of carbon steel and alloy steel.
ISO Metric Screw Thread Sizes & Tolerances Calculator Calculates basic major, minor and pitch diameters of the metric external (bolt) thread and internal (nut) thread according to ISO 724:1993 standard. In addition to basic size calculations, tolerance calculations of different tolerance classes can be done according to ISO 965-1:1998 and ISO 965-2:1998 standards.
Metric Tap Drill Sizes Calculates recommended cutting tap drill sizes to drill a hole prior to tapping ISO metric thread. The calculator is using a database to calculate the tap drill sizes which is in line with the drill charts given in the ISO 2306:1972 standard.
Metric Trapezoidal Thread Dimensions Calculates dimensional calculations of ISO metric single and multiple start trapezoidal screw threads.
Properties for Stainless Steel Metric Bolts and Screws Shows proof strength and tensile strength of metric bolts and screws made of stainless steel.
Self Tapping Screw Thread Dimensions Shows dimensions of metric self tapping screw thread according to the ISO 1478 standard.
PIPE THREADS
British Standard Pipe Parallel (BSPP) Thread Dimensions Calculator Shows basic dimensions of British Standard Pipe Parallel (BSPP) Thread according to ISO 228-1 standard.
BSPT Thread Sizes and Dimensions Calculator Shows basic dimensions of British Standard Pipe Taper (BSPT) Thread according to ISO 7-1 standard.
NPT Taper Pipe Thread Dimensions Calculator Calculates basic dimensions of general purpose NPT pipe threads (inch) according to ANSI/ASME B1.20.1-1983 standard.
Drill Sizes for NPT Pipe Threads Calculator Calculates recommended drill and tapped hole sizes for pipe threads (NPT - NPSC) according to ANSI/ASME B1.20.1-1983 standard.
ACME SCREW THREADS
Acme General Purpose Screw Threaded Rod and Nut Sizes & Tolerances Calculator Dimensional calculations of general purpose single and multiple start Acme threads according to ASME/ANSI B1.5-1997 standard.
Stub Acme Screw Threaded Rod and Nut Sizes & Tolerances Calculator Dimensional calculations of single start Stub Acme threads according to ASME/ANSI B1.8-1988 standard
Leadscrew (Power Screw) Torque and Efficiency Calculations Calculates parameters of a lead screw with Acme thread form. Calculated parameters by the calculator are required torque to raise and lower the load, efficiency and self-locking feature of lead screw.
BUTTRESS SCREW THREADS
Buttress Inch Screw Threaded Rod and Nut Sizes & Tolerances Calculator Dimensional calculations of Buttress Inch Screw Threads according to ANSI B1.9-1973 "Buttress Inch Screw Threads" standard.