T3P3 Kossel Mini Kit Release 3

Assembly Instructions:


Creative Commons License

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Think3DPrint3D Ltd


> Forward

Table of Contents

Each stage of the assembly process is documented in a separate Chapter as listed on the Documentation tab on the website listing, and shown below:

Introduction (this document)

Chapter 1 - Printed Parts Preparation

Chapter 2 - Base Assembly

Chapter 3 - Top Assembly

Chapter 4 - Carriage Adaptor Assembly

Chapter 5 - Spider Assembly

Chapter 6 - Endstop Assembly

Chapter 7 - Frame Assembly

Chapter 8 - Spider Installation

Chapter 9 - Timing belt installation

Chapter 10 - Endstop Wiring

Chapter 11 - Extruder mounting

Chapter 12 - Electronics, power plate and electronics cooling fan

Chapter 13 - Effector final assembly

Chapter 14 - Wiring

Chapter 15 - Printbed

Chapter 16 - Commissioning, Calibration and Testing

Chapter 17 - Test printing

Chapter 18 - Tidying up

Appendix A - Illustrated Bill of Materials

Appendix B - Illustrated Printed Parts List

Appendix C - Firmware upload procedures

Appendix D - Firmware configuration files

Appendix E - Duet Network connection

Appendix F -  Controlling the printer using Pronterface


The Mini Kossel is a delta robot 3D printer from Johann Rocholl, the designer of the original Rostock delta. It is an innovative and elegantly simple design featuring a small number of parts and easy assembly.


Our kit includes all the parts required to build our version of the Mini Kossel, plus a heated print bed and a genuine E3D V6 all-metal hot end. All wiring is cut to size and made up with plugs and connectors - no soldering or crimping is required. The electronics are concealed in the base for neatness and portability. The ball-ended carbon-fibre diagonal rods which are critical to print quality are accurately pre-assembled by us on a purpose-made jig.

Release 3 of our kit has been substantially upgraded: the main improvements include:-

  • Duet V0.8.5 32-bit ARM Cortex M3 electronics with ethernet and USB connectivity and micro-SD card socket for configuration and print files.
  • DC42 RepRap Firmware on the Duet - this takes advantage of the 32-bit processing power to provide true segmentation-free delta movement for improved smoothness and accuracy. Unlike most 8-bit firmware like Marlin, RepRap Firmware is precompiled and users should never need to modify or recompile it.
  • Heavier 20x20mm extrusions. These provide increased frame stiffness and allow the use of T-slot nuts which can simply be dropped into the extrusion channels when required, making assembly much easier.
  • DC42’s Mini-Differential-IR level probe which allows contactless level probing and in conjunction with the Duet and DC42 firmware enables full auto-calibration once basic calibration measurements have been made.
  • Break-out board for the hot-end wiring loom on the effector so that all the hot-end , fan and probe connectors can simply be plugged in - easier to connect and remove.
  • Pre-assembled and tested extruder.
  • Pre-assembled and tested E3D V6 hot-end.
  • Many minor tweaks and improvements suggested by our customers

Specifications for the standard machine are at http://reprap.org/wiki/Kossel. Printed parts designs are on our Github repository at https://github.com/T3P3/kossel - the original designs are in the main folder and our additional and modified designs are in the T3P3_additions folder.


We recommend you follow the steps listed below when building this printer:-

  • Unpack the kit and check that all parts have been supplied and none have been damaged during shipping. To help you with this, there is an Illustrated Bill of Materials in Appendix A  of these instructions, and each box or bag will have its own packing list. The main box should contain separate boxes and packs as shown below.


  • Contact us immediately by email or through the website if you find any missing or damaged parts.
  • Copy the software supplied on the micro-SD card to a safe place on your PC.
  • Read through each chapter of these instructions to gain an idea of what is involved and how long it might take, before starting on the work described.
  • Ensure you have the necessary skills to carry out the work, or enlist the help of someone who does.
  • Work on a firm table or bench in a clean dry well-lit area.
  • Observe tool safety and anti-static precautions (see below).
  • Ask for help if you run into any problems - email/ via the website and we will always do our best to resolve any problems encountered.

Tools Required

Essential: Supplied with Kit

Hex key, ball ended, long arm, 2.5mm

Hex key, ball ended, 2.0mm

Drill bit 3mm for reaming printed parts, with printed handle

Utility knife

5.5mm spanner.jpg

5.5mm spanner for M3 nuts

Essential: User-provided

Needle-nose pliers, small

Small screwdrivers flat-bladed and Philips or Pozidriv, e.g 3.0 x 75mm and PH1 x 75mm

Plastic or wooden mallet (or hammer +  wood)

Accurate ruler

Desirable: User-provided

Digital calipers



Electric drill/driver

Safety Precautions

This kit includes a sharp utility knife for preparing printed parts. You should observe all necessary precautions when using this, such as those at http://safetytoolboxtopics.com/Small-Tools/utility-knife-safety.html.

Printer assembly may also involve the use of other potentially dangerous tools. You should be competent to use such tools and observe reasonable precautions in doing so.

Electrostatic Discharge Precautions

You should be aware of the risk of electrostatic damage to the electronic components of this kit, specifically the Duet board and Mini IR probe . These components are fully tested with the other electrical items before packing the kit, and wrapped in protective anti-static packaging. Damage by electrostatic discharges during unpacking, assembly and normal use is not covered under our warranty. You should therefore observe reasonable anti-static precautions which are widely published on the internet. For a short and simple overview see Antistatic Precautions for Electronic Components on eBay. A more comprehensive document by Mini-Circuits can be found here.


Our thanks go first of all to Johann C Rocholl for designing this great printer (and its predecessor the Rostock), blogging about it and publishing the designs on Github. Thanks also to Builda3Dprinter and Blomker Industries for linking their build manuals from the RepRap Kossel Wiki, which helped to get us started with the first prototype build. Thanks to David Crocker (DC42) for his wide ranging contributions to RepRap and specifically his continued development of the RepRap Firmware, Panel Due and IR Probe, Christian Hammacher for his work on the web interface and RepRapPro for collaborating on the original Duet and RepRap Firmware. Finally thanks to all our customers who have emailed us with feedback on which we have based many of the R3 improvements.

Revision History

Release 1.0.0:  24 May 2014

To coincide with kit listing.

Release 2.0.0: 23 Jan 2015

Revised to cover kits now supplied with heated print beds and E3D V6 hot ends as standard.

Release 3.0.0: 25 October 2015

New Release 3 kit

> Forward