A threaded rod (aka allthread, studding, and in Australia, Booker Rod ) is a metal rod with threads welded on or rolled out. It is usually used as a frame construction part and as lead screws for the Z-axis. The most commonly used type of threaded rod in a RepRap or a RepStrap is a steel M8 (8 mm diameter) one.
Leadscrews are threaded rods used to lead a component on, for example the X-axis assembly on the Z-axis. For most RepRaps a common (straight!) threaded rod is sufficient, but for higher precision and reduced wobble you might want to use real leadscrews.
There are two main thread profiles for leadscrews, both of which are trapezoidal: Trapezoidal and Acme. The important but subtle difference is the angle of the thread flank. Be sure to get matching nuts.
A common problem when using leadscrews (also for common thread rod ones) is backlash. Because the nut has to be able to rotate freely around the rod, its threading is ever so slightly wider than the rods. Even when the rod is not turning, the nut can move a tiny bit up and down, which is the backlash. Reducing this improves the accuracy of the machine.
A common way to reduce leadscrew backlash is to preload: ensure the nut is in contact with the thread at all times. You can do this using two nuts with a spring in between. This keeps each nut pressed against the thread, reducing backlash. However, it will also make the rod harder to turn. More information and pictures in the article Backlash in Lead Screws: What It is and What to do About It.
The following table lists Threaded Rods vendors:
|3D Acessories Hub||IN||threaded rod||5mm & 8mm"||1000mm|
|Grainger||US||threaded rod||M5, M8, & M10||1000mm||sold in packs of 25|
|MSC Industrial Suply Co||US||threaded rod||M5, M8, & M10||1000mm||Oil finish or Zink plated|
|McMaster-Carr||US||threaded rod||M5, M8, M10, ...||...||Lots of sizes and choices. Ships to US only|
|RepRap-India.com||IN||threaded rod||M5, M8, M10, ...||...||Lots of sizes and choices. Ships to India only|
The following table lists Trapezoid and Acme leadscrew vendors:
|Enco||US||Imperial Acme threaded rod||1/4 - 5/8"||6'||8-16 TPI|
|HPC Europe||FR/IT||Trapezoidal rolled leadscrew||10-120 mm||1000-3000 mm||2-16 mm|
|RobotDigg||CN||Acme Threaded Rod Nema17||8mm||280 or 350 mm||2 mm|
|Roton||US||Metric threaded rod||10-28 mm||6-144" (152-3658 mm)||2-8 mm|
The following table lists Trapezoid and Acme leadscrew nut vendors.
|Vendor||Loc.||Product||Diameter||Pitch||Smallest outer diameter||Additional notes|
|Enco||US||Imperial Acme round nuts||.25 - 2.5"||4 - 16 TPI||0.68-7.5"|
|HPC Europe||FR/IT||Trapezoidal nut||10-60 mm||2-9 mm||17-90 mm|
|RobotDigg||CN||Anti-backlash Nut||8 mm||2 mm|
|Roton||US||Imperial Acme nuts||.1875 - 3.5"||2-20 TPI||.5"|
- Z Motor setup with leadscrews on the forum
- Acme versus Threaded rod on the forum
- Alex English. "Accuracy vs precision and threaded rod vs leadscrews in 3d printers".