Threaded rod

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Threaded rod

Vitamin

Varilla-roscada-r1.jpg
Threaded metal rod, used as lead screws and for the frame.
Wikipedia none

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.

Contents

Leadscrews

general motion control

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.

Insights Regarding Leadscrew Usage For Fast Axes

  • Take steps to avoid entire lead screw moving in end-to-end direction
  • If you're unsure about required torque, see Oriental Motors' sizing tools
  • Lead screw and nut must be fixed in aligned position, (relative) twist will bind up the nut

Preloading

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.

Vendors

Threaded Rods

The following table lists Threaded Rods vendors:

Vendor Loc. Product Diameter Length Additional notes
Folger Technologies, LLC US Threaded Rod M5, M6, M8, M10... 1000mm/custom cuts Ships Worldwide
3D Acessories Hub IN threaded rod 5mm & 8mm" 1000mm  
Alfa-Tech3D DK Threaded rod M2 , M3, M4, M5, M6, M8 & M8x1, M10 200-800mm Shipping worldwide
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 Zinc plated
McMaster-Carr US threaded rod M5, M8, M10, ... ... Lots of sizes and choices. Ships to US only
DIY-India.com IN Threaded rod M5, M8, M10, ... ... Lots of sizes and choices. Ships to India only
Makemendel IN Threaded Rod M5, M8, M10, ... ... Lots of sizes and choices. Ships to Worldwide

Leadscrew

The following table lists Trapezoid and Acme leadscrew vendors:

Vendor Loc. Product Diameter Length Pitch Additional notes
Alfa-Tech3D DK Trapezoidal Threaded 8 mm 300mm, 500mm 2 mm Shipping worldwide.
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  
Makemendel IN ACME Threaded Rod with Nut 10 mm 255mm 3 mm custom length Threaded rod is also available.;
TaoTac.com VN ACME Threaded Rod with Nut 8 mm 300 mm 3 mm  

Leadscrew nuts

The following table lists Trapezoid and Acme leadscrew nut vendors.

Vendor Loc. Product Diameter Pitch Smallest outer diameter Additional notes
Alfa-Tech3D DK Brass Nut & Anti Backlash nut 8 mm 2 mm Shipping worldwide.  
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"  
TaoTac.com VN Anti-backlash Nut 8 mm 2 mm  

External Links