Angle of acme thread is _______

Explanation:

Trapezoidal threads: 

• These threads have a profile which is neither square nor V thread form and have a form of a trapezoid. Different forms of trapezoidal threads are ACME thread, Buttress thread, Saw-tooth thread, Worm thread

ACME thread:

• It has an included angle of 29°.
• These are used in lathe lead screws.

Buttress Thread:

• In this thread, one flank is perpendicular to the axis of the thread and another flank is at 45°. These threads are used in power presses, carpentry vices, gun breeches, ratchets, etc.

Square thread: 

• In this thread, the flanks are perpendicular to the axis of the thread. This is used for transmitting motion or power. E.g. Fly presses, Screw jack, vice handles, cross-slide and compound slide, etc.

Knuckle thread:

• The shape of the knuckle thread is not trapezoid, but it has a rounded shape. It has limited applications. It is used for valve spindles, railway carriage coupling, hose connections, etc.