I'm building a Kossel Mini, and I'm stuck on the extruder motor holder.

My Kossel came without instructions, I was given a set of instructions by a friend (the "Kossel Build Guide" by Blomker industries). I also found some instructions on the net. However, my components are different from those in the build guides.

The question is how these components fit together.

I'm pretty certain the stepper motor should be connected to the big black components (labeled (1) and (4) in the picture). The 4 holes in these components correspond to openings in the stepper motor; and the stepper motors for the vertical carriages, were connected in a similar way to their respective holders.

The round thing, second from the left on the bottom, (labeled (2) in the picture) presumably goes on the axis of the stepper motor. Once again, a similar procedure was needed for the motors that will move the vertical carriages.

The screws on the right, labeled (3), are 1 cm long and 3 mm wide.

The other screws are 2 cm long and 3 mm wide.

The stepper motor is a Wantai Stepper Motor Model 42BYGHW811 .

I have e-mailed the company where I bought my kit and am awaiting their answer. Meanwhile I'm hoping to get some advice here.

Apparently the usual stepper motor for a Kossel Mini is Nema 17. Searching on "42BYGHW811" I mostly find datasheets. Using "Nema 17 mount" or "Nema 17 mounting screws" as search terms, I find a lot of images with a component like (1). But nothing on how this and the other components should be put together for the motor holder for an extruder for the Kossel Mini.

Parts of the extruder

  • $\begingroup$ Searching further, it looks like part of this is for the extruder head: something like this image. $\endgroup$ Mar 13, 2016 at 19:06
  • $\begingroup$ Did you ever get a reply from the vendor? Also, a link to the product page would be very useful. $\endgroup$
    – Greenonline
    May 15, 2019 at 7:52

2 Answers 2


Have a look at the image provided in this seller's part description. it probably says more than my words could (which would also only rely on images - your parts just looked like I saw them somewhere before).

3D printer parts right hand Bowden Extruder kit set no motor compact extruder aluminum alloy for

Right hand Bowden Extruder kit

  • 1
    $\begingroup$ There are some more images from all sides when you scroll down the description $\endgroup$
    – kamuro
    Mar 15, 2016 at 10:17
  • $\begingroup$ Your link has died, unfortunately. If you provide the title (i.e. description) of the item as the link text, it would make it easier for products with dead links to be located afterwards... see my edit to illustrate what I mean. $\endgroup$
    – Greenonline
    Aug 13, 2018 at 15:32

The extruder is an MK8 derivative, I think.

After a lot of searching, the closest that I could find (with an assembly diagram) is this product which has more or less the same parts as yours (apart from the small black bolt and sleeve - used as the axis - which you don't have): [Improved Version] YOTINO Right Hand MK8 Remote Bowden Extruder Accessories 1.75mm/3mm Filament All Metal Remote Extruder Frame Block for Reprap 3D Printer Kossel Prusa.

These are the parts:

16 parts

This is the assembly process:

Assembly process

This is the completed extruder:

Completed extruder

Also, whilst this is not the same beast, this link shows a detailed assembly which could prove useful as a cross reference: RepRapWiki - Extruder assembly

In addition, w.r.t the Blomker guide, there are a number of versions of the same guide that I've come across in the past:


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