Kossel Mini build : Part 5

Recap :

Kossel Mini build : Part 0 – a brief explanation of intent and also sources where I got the parts

Kossel Mini build : Part 1 – assembled the top triangle frame, as it seemed like the simpler of the 4 main components

Kossel Mini build : Part 2 – assembled the diagonal rods by leveraging parts used on the bottom triangle base

Kossel Mini build : Part 3 – while building the effector, encountered some fitting issues on both the plastic and nylon screws.  A combination of dremel and tap and die were used to make things fit.  Also finished the auto level probe.

Kossel Mini build : Part 4 – the diagonal rods were installed to the effector, and the J-Head hotend was also attached to the effector.  Also finished the bottom(base) of the Kossel Mini.


The rails finally arrived, and after a minor QA issue(that the vendor was quickly able to remedy) I can continue with the Kossel Mini build.  This build session took longer than anticipated – it happened over several nights from Friday to Sunday, and I finished write up on Monday evening.  And now, back to the build.

I used the following parts

  1. 6 x endstops
  2. 6 x M3x8mm screws
  3. 6 x M3 nuts
  4. 3 x micro switches
  5. 6 x M2.5x8mm screws

I also needed:

  1. 6 x wires to solder to the switches
  2. shrink tubing to seal the soldered ends
  3. female headers to solder to the ends of the wires(so I can connect them to the RAMPS board)


The endstop assembly is pretty straight forward, each piece gets 1 x M3x8mm screw and a M3 nut as shown below

rail end stop assembly

Three endstops will also require 1 x micro switches to be added via 2 x M2.5x8mm screws.

I soldered wires to 3 micro switches.

endstop switch soldered


Micro switches are screwed onto the endstops via 2 x M2.58mm screws.

endstop with switch and screws


The rails need some preparation as well:

  1. 3 x 400mm rails
  2. 48 x M3x8mm screws
  3. 48 x M3 nuts

The rails have 16 holes and each hole gets a M3x8mm screw and a M3 nut.

putting screws in the rails

nuts on the bottom of rails

These rails, 1 end stop, and 1 end stop with microswitch goes on each of the three 600mm extrusions.

rails on extrusions

Each extrusion also got an endstop and an endstop with a microswitch.

rails with endstops

I measured out 50mm on a caliper and using it’s depth gauge, spaced out the endstop with the microswitch so the three rails would all have the endstops with microswitch, the rails, and the endstops spaced out all the same.  This is my attempt at trying to avoid endstop calibration headaches.

displacing the endstop

I also snaked the stepper motor wires through the base, so it can be inserted into the vertical extrusion.

stepper motor wire

stepper motors snaked in 1

stepper motors snaked in 2stepper motors snaked inall stepper motor wires snaked throughVertical extrusions are then inserted into the base, leaving the stepper motor wires out. And also the top(not pictured). The wires are them twisted until it becomes a small, tight bundle of wires.

stepper motor wires twisted

I found that if the wires are tightly twisted and then inserted into the side channel of the extrusion, the wire bundle will unravel and hold itself in place.

twisted stepper motor wires inserted into the extrusion


As for the belts, the kit that I purchased included a single 4 meter length belt.  What I did was measure out and cut three even belts.

4m stepper motor belt 3 x stepper motor wires

Again, this is so that calibration will be easier later on.

First, the carriages are attached to the rail platforms.

carriage on rail platformEach of the three belts were looped over and the upper part was tied like below:

top belt secured

I made sure all three had exactly the same number of teeths – again, to ensure that all three vertical rods would be the same.

bottom belt secured

The same thing for bottom belt.  There was a LOT of leftover belt from the bottom, but it did not interfere with the stepper motor on the bottom base.

Finally, I am using a RAMPS 1.4 shield and a Arduino Mega 2560 that I had been using from my previous printer as the controller.

Using whatever screws I had leftover from my kit and spare parts drawer, I was able to mount the RAMPS board on the top of the Kossel Mini.

RAMPS and mounting parts

Note that I am using 4 nylon washers(2 on each screw) that is quite hard to see.  The parts are assembled like below:

RAMPS mounting parts 2RaMPS mounting pars complete

RAMPS mounted on top


Oh boy, the machine is nearly complete! But this is where I’ll stop for today.



4 Replies to “Kossel Mini build : Part 5”

  1. what connector do you put on the end of the stepper motor wires? i have nema 17 motors 4 wires on each but no connector on the end

  2. I used 0.01″ male headers on my RAMPS board, I used female 0.01″ female headers on the wires. The only thing is you have to figure out the windings.

    Let me know if you want to in know more information.

  3. Pingback: Kossel Mini build : Part 7 – Minuk.Net

  4. Pingback: Kossel Mini build : Part 6

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