Make A Prusa i3 MK2 Clone – Build Notes

Build Notes:

This page contains the notes I made from Jules Gilson you tube video. This is a quick resource for finding comments Jules mentions in his video. 

This information should not be considered complete. Im hoping to build a Prusa soon and I will update this blog with my notes as well. For now this is a place for the notes to live in public view. See Jules Gilsons website for his documentation. 

This is a draft and should be treated as such. Each of the sections below should follow his videos in order. If you find errors. Please comment below.


This is the video series. It may seem a bit slow at first, but the information is fantastic. It’s worth watching the entire series. 


The BOM / parts list can be found on Jules Website. I wrote down what he calls them, here are my notes:

BOM – Original I3 Prusa

Linear Rods (6)
Idler Bearings – for belts
Length of belt &16 tooth pulley
3mm nylon filament HDPE tubing – for wiring harnesses (run in wires)
ooos nest – build plate 6mm aluminum
Hex Cap Bolts
Springs for extruder
Mark 8 pop gears
Tie Wraps
Hob key (Name?)
half nuts / Thinner m-10 nuts
M10 washers
5-meter length of silicon wire
set of 12 linear bearings
extruder bearings
m3 square nuts (4 sides, rather than 6)
M3 & m10 penny washers
M3 nylock nuts
3MM heated bed aluminum (mark 42 will be available soon) – 24 volts is good, 12 may be standard
4 NEMA 17 – Grunty one for Extruder
hot end – E3DV6 Clone – 1.75mm filament (3 mill also available, probably not recommended) With heat thermistor & heat cartridge
14-piece rep-rap wiring set
Limit switches (3) – His didn’t fit
Using Toms Modified prints
part cooling fan – 50mm 12-volt fan
Complete controller set –
• Arduino Mega
• RAMS Board
• Large LCD Controller – SD Card, Pot,
• 5 stepper driver – H-Bridges, DRV(maybe be an upgrade)
Lead Screws 8mm – (Rather than 5mm threaded rod) With Lead-screws
Proximity Sensor 5 Volts, Maybe 12
Flexible Couplings for Lead Screws / Stepper Motor (For Alignment)
3D Parts – ABS
M8 Washers
M3 Nuts
M8 Nuts
Assembly Kits – Connectors 1, 2, 3, 4, 5, pins_for wiring
MOSFET – for RAMS Board
-He might use RAMS board to control external SolidState
Fuse holder_4-Blade_Polyblade Fuses_Up to 40A
Raspberry Pi – For Octoprint (For Network Control)

Square adhesive cable holder / mount

Small, Medium, Big Crimps – Dupont Style Connectors
Reprap 14 – wire cable kit

Frame Build


X-Axis Build

X-Axis Build

On Prints – Tom added extra section for limit switches

Extruder Print Had to drill holes & Dremmel, and zip tie channels – Dremmeled & dug out infill.

18 mill M3 Hex Caps
Drill & Tap limit switch holes

Z-Axis Build


Lead Nut is different
• Tom uses 3D Printed sandwich for M5 Nut
• Holes on nut is smaller than Toms Axis parts
• Jules drilled out the middle hole of the sandwich. Then slotted lead screw nut

More Build Notes

Hobb Gear_Mark 8-Too Big, Need to modify STL Files??

And More Build Notes...

Heated Bed_Not flat_Face it?

His is bent from bottom_Uses
• 5mm square bar aluminum to shim upwards

Glue for Thermocouple?

Initial Marlin Setup

Marlin Setup – 2016


Changes Build Date _ Configuration
Changes name- comes up on LCD
Thermistor – Can be set by name Set Temp sensor number – He did 100K, 4.7K Pull-up Resistors, Setting #13
Sets Heater max temp 275C for all metal Hot End
Left Hot End PID Alone for now – Because all tuned – Ultimaker Defaults
Bed PID – Turned on_Can be PWM modulated through MOSFET

Endstop Pullups – Disabled all
Proximity sensor will be tested later
Invert End Stops
Steps per mm for all axis –
• 1.8deg steppers 16t, 2,, pitch opn x & y. Z = 1.8deg, 8mm/rev screw.
• Extruder guessed by using circumference of hobbed area (7mm dia =27mm cir) as mm/rev
• Calculates to mm/rev = 152.38 steps/mm

Define_AXIS_STEPS_PER_UNIT ( 100, 100, 400, 150)

JG slowed down for default testing
Default: 300, 300, 5, 25

define DEFAULT_MAX_FEEDRATE { 200, 200, 3, 25 }

Reduced Jerk on X & Y axis for now:
Default jerk x & y = 20

Defined fix mounted probe

Roughly set
Default = 10
Set to = 21
Along x axes = 10 mill further back than the nossel???

Define z clearance_Between_Probes
Default = 5
Set to 5
to avoid hitting anything when beginning – dont hit bolts and nuts that hold nuts / build plate

Define invert y_dir = True

When Homing:
Z_Homing_Height – uncommented to enable – increase to not hit bed nuts
Default = 4 , lease as is – maybe needs more_define during testing

Travel Limits after homing
Reduce x travel

define x_min_POS -10

define x_Min_POS 0
default = 0
Set to -10
amount When actual nozzle is on the s to the left of the probe – when probe goes to 0 nozzle is 10 mm to the left – this accounts for this

Max print area 190
150 – Increase during setup

Both temp disabled during setup
Comment out min_software_endsops
Will be enabled again during setup
Prevents going past min and max set above (Max build area)
Disabled so we can set in software rather than changing firmware

Bed sensor – Increases points of inspection to 16 points for leveling mesh
Define Grid_Max_Points_x 3 –> 4

Puts points off the bed?
Left_Probe_Bed_Position 15 –> 30
RightProbe_Bed_Position 170 –> 160

EPROMM Settings –> Uncomment

Setup for LCD
DOGLCD –> Uncomment

SD Card Support – On LCD kit
SDSUPPORT –> Uncomment

Later set up stuff for board – rotary encoders

Allow to home axis individually

Perhaps the correct Driver


Changes many settings

Uses comparator WinMerge To compare code changes


Load Firmware

Wipe EEPROM of Arduino MEGA

JG has EEPROM wiping program

18mins of Code video

Upload Marlin – Compile & Upload

Connecting Electronics

Connecting Electronics Build Notes

Stepper Motor Wires were wrong way around. Others came without connectors.
Colors matched Between RepRap Cable Kit & Stepper Motors
For Steppers – Pairs are the two wires with a resistance between them, Polarity is not important, but must be wired in pairs.

In RAMS board
• Two Top – Need to wired to a pair
• Two Bottom – Need to be wired to a pair

Limit switches_S-+_Maybe labeld on RAMS board

Proximity Sensor
Thought he bought 5V, he didn’t
He put voltage divider together and that is on the website
But eventually, the proximity sensor worked fine with 5-12 V – so was needed
Black Signal
Blue Neg
Brown – Positive,
Plugs into zed minimum on Rams

Part Cooling Goes into 9

Hot end cooling fan – Thinks 12 volts input from Power Supply

Before you put stepper drivers in – don’t forget to put jumpers in

Stepper Driver – Needed to file plastic jumper legs to get them to fit in RAMS board.

Properly Configure Marlin

PronterFace – Software For PC
Prusa Drivers
Probably does not work on a mac
Link on JG website

Using Power Supply
Starting without Heated bed
Leaving it unplugged

Centered Machine before starting
Make sure Proximity Sensor is well down below the nozzle
-So it kicks in before crashing extruder

Open Pronter Face
Set Com
Do not load anything in Arduino IDE
Baud Rate 250,000

Press – Connect
Heater reports
Bed Reports

  1. Set up limit switches
    Min Limits


M119 – Get status of the printer stops / limit switches
If they are all on – it means switch polarity is reversed
Check all Switches, run M119 again

In Arduino IDE_Update

Because we are changing ZED
• Also change

Maybe also look at extruder motor is running in a different direction

Save, Compile, and Upload
-Keep in mind only one software can be connected to arduino at one time.
ie. disconnect PrompterFace if uploading on arduino for example – Arduino automatically disconnects after uploading

Retest to make sure it is working

See if motors move, and move in the right direction
+x should to the right

If direction is reversed

Enable Limit Switches

0,0,0 Extents

Use some kind of measuring tool
X-Axis hitting min limit switch
Measure from Extruder Nozzle to Safe Area on Bed – He had 7mm
update – in homing section
• x_min_POS
— He needed to move the limit to the left by 7mm, value is -7mm because it REDUCES the build area by 7mm

Safe Homeing section
– Was disabled, now enable it
• Z_SAFE_HOMING –> Uncomment

Home Axis Individually to check
– Be careful Z-Does not crash into the bed

M114 – Shows Coordinates of Nozzle

STEP 4 – Maximum Extents

Was set low during initial configuration, so comment out
Comment out — > #define MAX_ENDSTOPS….

Every time the machine powers, or upload the firmware –
• It looses home position
• Be sure to rehome each time

22:00 minutes in video

For max_stops move machine with PronteFace until limit switch, then send M114 to see where the X axis is

For y-axis, the nozzle needs to clear the back nuts

DEFAULT_MAX_FEEDRATE (200, 200, 8, 25)
zed increased from 3 –> 8

On z-axis, when home is clicked, z will move up a certain amount as set
– In therory dont need any, set to 4 to make sure out of sensor area
– move z to top / positive, move it almost to top
– remember now you will need to add 4 to top
– Move z down 4
– Run M114 to check position of axis
• ZED_MAX_POS –> insert 11

COMPILE ERROR –> can not home

BACK_PROPE_POSITION set to outside of build area

Step 5
Bed Leveling

Bed leveling is based on position of probe rather than nozzile
+23 on x
+9 mm on the y
z = to, just to keep things safe


NExt set up the most left point you wnat it to probe
• Position of the probe sensor
— 180, will make it 25 from left side and 25 from right side
— 9
— 154 – 9 = 145

Mesh bed level = G29

Step 6

Set up Z-Probe
Set to 1mm above the nozzle
• Above Nozzle, below sensitivity nozzle
M119 needs to set this off
41:22 in video

• So we can go below 0
Send Code
G0Z – Sends Z to zero
114 – Check position

— Sometimes even when you disable MIN_Software_Endstop, it will still not go below 0
• Sometime you need to update z_MIn_POS, then recompile & reload software
M114 , ensure Z = 0.00
— Move Z down 1 (BE CAREFUL)
— Put a peice of paper under the nozzle
–Move down 0.01, until paper is stiff
•Z_PROBE_OFFSET as needed

Watch video for more.

STEP 7 – Extruder

Check Extruder Speed
Cold Extrusion is prevented

And thats the end of me weekend!

More to come later on. Hopefully these notes are helpful. If you find errors, which im sure there are some because this is a draft, please comment below.

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