Acme threads are a common screw thread profile, which offers high strength with ease of machining and assembly. A screw thread is a helical or tapered structure used to convert between rotational and linear movement or force Typically found where large loads or accuracy is required as in vises or the lead screw of a lathe. A vise or vice (see under miscellaneous spelling differences) is a mechanical Screw apparatus used for holding or clamping a work piece to allow work to A leadscrew is a screw specialized for the purpose of translating rotational to linear motion A lathe (ˈleɪð is a Machine tool which spins a block of material to perform various operations such as Cutting, Sanding, Knurling Standardized variations include multiple-start threads, left-hand threads, and self-centering threads which are less likely to bind under lateral forces.
Threads formed around a shaft are used to translate rotational motion into linear motion. In this way fasteners such as screws and bolts convert the torque of a screwdriver or wrench into a compressional holding force. A torque (τ in Physics, also called a moment (of force is a pseudo- vector that measures the tendency of a force to rotate an object about The linear motion is also used to move or position mechanical components, such as a tool post on a metal-working lathe, or to raise or lower a garage door.
Precursors to the Acme Thread
The most common profile for threads in a fastener is a V-form; the threads, if sliced parallel to the shaft would describe a series of Vs, representing the apex of the threads and the valleys between them. V-form threads are narrower and weaker closer to the apex, which makes them susceptible to shearing off under loads which would otherwise not cause the screw or nut body to fail.
Jack screws for moving large structures, bench vises and C-clamps are common examples of the type of screw application which require high strength, and square threads were developed to address this issue. Screwshavings2 smPNG|thumbnail|Damaged jackscrew recovered from Alaska Airlines Flight 261]] A jackscrew is a type of jack which is operated by turning a Leadscrew This article refers to the clamp used to hold together two workpieces Square threads are cut with a square profile, with a zero degree thread angle which provides a stronger, more robust bearing shoulder for the rotating shaft, and subsequently far more strength than a V-form thread. However, square threads are difficult to machine.
The Acme Profile
The Acme thread was developed as a compromise, to offer better strength than a V-form while overcoming the problems with the square thread form.
The Acme thread form uses a 29 degree thread angle with flat apex and valley.
External links
- Threaded Fasteners
- Screw Thread Forms
- International Thread Standards
- Comparision with other power threads
- Drawing of an Acme thread
- Trapezoidal coarse thread
- Trapezoidal fine thread
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic