Kossel Mini build : Part 6

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.

Kossel Mini build : Part 5 – the rails have been installed to the pillars and the printer has been assembled.  The RAMPS 1.4 shield was also mounted on the top of the printer

I ran into some unexpected issues and was not able to work on the printer.  Let’s resume.  From my last post, I skipped on the detail on how the top of the frame was mounted.  As mentioned before, I tried to even out all the components for the 3 vertical extrusion rods, as a lot relies on the three vertical extrusions.

Using a caliper, I ensured that the top frame was 15mm from the top end of the extrusion.

15mm from the top
15mm from the top

Once the screw was tightened, I tightened the top screw to help hold the top frame in place with the belt installed.

the screw is tightened enough to hold the top frame piece in place
the screw is tightened enough to hold the top frame piece in place


The wires for the stepper motor AND the endstop were carefully routed to the RAMPS shield.  I just wired them arbitrarily from the farthest from the RAMPS board, in clockwise direction, X, Y, and Z.

wired up RAMPS

I used the following wiring diagram, and everything was very straight-forward, from blomker’s PDF;

from Blomker's PDF
from Blomker’s PDF

After loading the firmware, I used Blomker’s customized Pronterface config settings as a starting point.

First, I had to assemble the extruder, which in a bowden setup, is apart from the heating element, connected by a PTFE tube.

The extruder piece is interesting in that it required a lot of clean up – the bearing slot had support materials intact, and the hole for the gear was too small.  I found that removing the support for the bearing still required a few passes with a dremel to remove burrs and rough edges.

bearing installed into extruderThe nozzle was easily screwed in, and using whatever screws I had left over, I assembled it to the geared stepper for fitting.  I found that I had to hand tighten the bearing while turning the bearing.  There was a point of tightening where the bearing locks and does not move.

Trying to install the geared tooth onto the geared stepper was simple, installing that onto the extruder frame was not.

extruder assembly 2

widening hole on extruder

After several passes with the dremel to widen the hole, I was able to mount it on the geared motor and turn the geared tooth bit without it rubbing against the the extruder piece.


Unfortunately, the printed kit I bought did not come with the mounting piece for the extruder, so my aim is to get the printer running and print the needed piece.

Also, I fed in the PTFE tubing from the exturder to the effector.


Hopefully I can start calibration soon!

One Reply to “Kossel Mini build : Part 6”

  1. Pingback: Kossel Mini build : Part 7

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