Modified 3D Printer

The Project

This page details the modifications made to the original “Eaglemoss Vector V3 Printer” build, the full details of the project and a guide to its use.

“Eaglemoss” have ceased to exist as a resource for those of us who built, in kit form, or bought ready built. As such, there is no longer any support, from their web pages for the Software, Firmware or replacement parts. So no guidance on replacing parts unless you have all 100 issues of the magazines to provide build details and component information. Some continued support, however, can (at present) be resourced at the “Vector 3 User community” here and most electrical parts can be purchased elsewhere on-line.

The tables below detail each issue content for your reference:

Eaglemoss” Print Issue Index


Hence, and after the demise of my original “Eaglemoss” main board and the auxiliary Stepper motor test board (power supply connections errors) it was decided to modify the original hardware, software and firmware as detailed here. Sounds complicated but following the steps below can be completed by a competent user.

The original software offered an integral slicer which gave reasonable quality but lacked the features of other propriety “slicers”. It ran on Windows and connected to the printer via a USB.

New Software and Firmware


Slicr3” is a far better slicer, with greater options and with direct integration to “Export” and print the “sliced” file directly across the LAN to the Raspberry Pi. Download it from this link

Octoprint” running on a Raspberry Pi provides a faster and better quality print. It is the preferred software which forms the basis of this modification. Free to download, provided by a female Dutch programmer and a growing library of plugins from 3rd party developers.

“Arduino IDE”

For ease of use I use a USB switch to allow me to select the Pi or my PC to the Arduino/Ramps board.

So Download the “Arduino IDE” for Windows (32/64 bit) zip file. Then Download “Octoprint” from here and use Etcher again to flash this image to an SD Card.


Download the Marlin firmware here . The downloaded folder Marlin-2.0x contains a Marlin folder containing a Marlin Arduino file. This can be opened in the Arduino IDE but will fail compilation with many library errors. The Marlin firmware MUST be “BUILT” before it can be compiled successfully. This procedure is simplified by viewing the “youtube” video here. Results within the VS Software permit editing the configuration files and then uploading to the Arduino 2560 board.

Watch this video for Configuration settings

Hardware Required

Arduino Mega ADK

Raspberry Pi

Reprap RAMPS 1.4 3D printer control panel kit.

A4988 Stepper Motor Driver Carriers

Stepper Motors

Step Angle/Step Angle: 1.8 °
Voltage/Rated Voltage: 12 V
Nominal current/Rated current: 0.4 A/phase
Resistance/resistance: 30 Ohm/phase
Induk Dance/Inductance: 38mH/phase shift
Securing moment/Holding Torque: 32g (2ft) (40oz in)
Locking Catch moment/Detent Torque: 1.6 N. cm Max
Torque/Rotor torque: 35 g/cm²
Cable slots/Lead Wires: 4
Length/Motor Length: 34 mm
Thread diameter/shaft diameter: 5.0 mm
Weight/Motorised Weight (kg): 0.22
Line Connector/Lead Wires Connection: 4 wires/4 leads: Back – A + Green – Red – B + Blue – B channel

The RAMPS 1.4 Stepper motor carriers for the X, Y and Z axis each have 3 Jumpers to configure for the Step Angle of the Stepper Motor. See the table below:

Configuration for A4988 jumper step size

no no no full step
yes no no half step
no yes no 1/4 step
yes yes no 1/8 step (use this for each driver)
yes yes yes 1/16 step

The RAMPS Board

The RAMPS board cannot use the original “Eaglemoss” Stepper Motor driver boards as, whilst using the same chip, the carrier is a different size and pin assignment to the recommended A4988 boards.

However these are preferential in that the motor current is fixed on the original board but is adjustable on the A4988 board. Furthermore the “Eaglemoss” boards run at around 0.7A which was overdriving the motors by quite a bit, and this makes them run hot. It will also shorten their life. By lowering the current it makes them run cooler and a little quieter.

From the above specs it can be be seen that the current rating is 0.4A so it is required to set the “Pololu” boards accordingly. Do this using the following method:

Power the bread boarded driver with 5v on the VDD pin and GND pin connected to 0v. With the 4 wire plug for that stepper motor unplugged and set the variable resister adjuster as shown below.

A voltage of 0.56v is required provide a motor current of 0.7A but lowering this to 0.38v gives a motor current of 0.475A and makes them run cooler and a little quieter.

See this link for the “Pololu Carriers” for full details.

See this link for a definitive guide on setting the A4988 Stepper Driver.


Powering the Arduino, Raspberry Pi and the RAMPS PCB (with all Server Motor Drivers inserted).

The original V3 printer PSU supplied just one +24v dc via a 3.5mm jack plugged into the controller PCB. This was reduced to +5v and 12v by 7805 and 7812 voltage regulators.


To continue using the original Power Supply follow this link for detail on “using 24v on the RAMPS 1.4 board“.

Using an ATX power supply

Hardware, Firmware and Software


This section seeks to resolve issues that were found when using the Marlin/Arduino configuration with Pronterface:

Setting the “endstops” and the “axis direction” was initially thought to be sufficient to facilitate correct motion control. X and Y axis appeared OK but the Z axis was more complex. Below are some references used to correct functionality.


define DEFAULT_AXIS_STEPS_PER_UNIT { 80, 80, 3200/0.8 , 500 }

define DEFAULT_MAX_FEEDRATE { 300, 300, 150, 25 }

define DEFAULT_MAX_ACCELERATION { 5000, 5000, 5000, 50000 }

define DEFAULT_ACCELERATION 1000 // X, Y, Z and E acceleration for printing moves

define DEFAULT_TRAVEL_ACCELERATION 1000 // X, Y, Z acceleration for travel (non printing) moves

define DEFAULT_ZJERK 0.4





define DISABLE_Z false



define HOMING_FEEDRATE_Z (50*60)

Configuring Endstops on Ramps 1.4 With Marlin Firmware – @section Homing

Motion Configuration on Ramps 1.4 With Marlin Firmware @section Machine

  • The Arduino firmare for can be found here.
  • The Raspberry Pi provides the “Octopi” image was downloaded from here.