Internal ISO Metric Trapezoidal Screw Threads Table Chart Sizes TR240

Internal ISO Metric Trapezoidal Screw Threads Table Chart Sizes TR240 - TR1120

ISO Metric Hardware Engineering Data
Fastener and Screw / Bolt Design, Formula and Calculations

Trapezoidal threads are typically pecision rolled screw profiles and often used for lead screws and is similar to the Acme thread form, except the thread angle is 30°. It is codified by DIN 103. Although metric screw threads are generally more prevalent worldwide than imperial threads, the Acme thread is very common worldwide, and may be more widely used than the trapezoidal metric thread.

Trapezoidal threads are defined as follows by ISO standards: ISO 2901, ISO 2901, ISO 2903, ISO 2904 and ISO 103. Gages ISO metric trapezoidal screw thread are defined in the DIN 103-9.

These dimensions are determined by the following formula:

H₁ = 0,5P
h₃ = H₄ = H₁ + a_c = 0,5P + a_c z = 0,25 P = H₁ / 2
d₃ = d - 2 x h₃ = d - 2(0,5P + a_c)
d₂ = D₂ = d - 2z = d - 0,5P
D₁ = d - 2H₁ = d - P
D₄ = d + 2a_c
s = 0,267 95es
R₁max. = 0,5 a_c
R₂max. = a_c

Where:

D = major diameter of internal thread
d = major diameter of external thread (nominal diameter)
D₂ = pitch drameter of Internal thread
d₂ = pitch diameter of external thread
D₁ = minor diameter of internal thread
P = Pitch
H = height of fundamental triangle
H₁ = height of basic profile
a_c = crest clearance
es = fundamental deviation on external threads

ANSI Inch Unit Hardware Design Guide
Length of Screw Thread Engagement per. ISO 965-1 Calculator, Formula and Table Length of engagement of mating threads is selected to utilize full tensile strength of a bolt prior to shearing and nut threads.
External ISO Metric Trapezoidal Screw Threads Chart TR320 - TR1120
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External ISO Metric Trapezoidal Screw Threads Table Chart Sizes TR8 - TR315
External ISO Metric Trapezoidal Screw Threads Table Chart Sizes TR320 - TR1120
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