Printing Instructions

Get the files:


These are the recommended print settings for the PrimoDrop extruder parts:



  • PETG for all the parts


  • 0.2 mm layer height

  • 4 Perimeters (to make the parts rigid)

  • 6 Top/Bottom layers

  • Infill >= 25 %

  • Infill pattern is up to your preference

  • maximum nozzle size should be 0.4 mm, especially for the gears


  • PrimoDrop-Main

  • Big-Driven-Gear

The parts are already optimally orientated to print. Set the support angle over 45°, so that the filament path has no supports 



  • Hex key 1.5 mm

  • Hex key 2 mm

  • Hex key 2.5 mm

  • 8mm open-end wrench or pliers

These Hex key should have arrived with your Ender 3





Items from Bag 1:

  • 1 x M4x18

  • 1 x 624 ZZ ball bearing (diameter: 13 mm)

Place the ball bearing in between the two legs of the idler and screw into place using the M4 screw. Make sure to insert the M4 screw on that side of the idler where one of the legs is slightly thicker than the other.


Items from Bag 1:

  • 1 x M4x18

  • 1 x M4 washer

  • 1 x M4 square nut

  • 1 x M4 knurled nut

  • 1 x Spring

Take the M4 screw and the washer and screw them onto the PrimoDrop-Main body using the M4 square nut. Then screw the knurled nut onto the the M4 screw. Now place the spring on the screw.


Items from Bag 1:

  • 1 x M3x16

Use the M3 screw to attach the Idler to the PrimoDrop-Main body. Do not overtighten the M3 screw just screw it in until the head of the M3 screw touches the idler.


Either use the spare bowden coupler that came with your Ender 3 or use the provided bowden coupler and screw it into the PrimoDrop-Main body. It is recommended to use the provided bowden coupler.


Items from Bag 1:

  • 1 x M5x35

  • 1 x M5 washer

Items from Bag 2:

  • 1 x 688 ZZ ball bearing (diameter: 16 mm)

  • 1 x M5 Sleeve

  • 1 x Hobbed Gear


First thread the M5 screw through the printed 'Big-Driven-Gear'. Then place the M5 washer on the M5 screw and either use a 8 mm open end wrench or pliers to screw the M5 Sleeve onto the M5 screw. Now place the ball bearing on the M5 Sleeve and screw the Hobbed Gear onto the M5 screw (orientated like in the picture). Tighten the grub screw on the Hobbed Gear, to secure it.


Items from Bag 3:

  • 1 x M3x14

  • 1 x M3 washer

  • 1 x M3 square nut

Before attaching the 'Big-Driven-Gear' to the PrimoDrop-Main body take one of the M3x14 screws, one M3 washer and one M3 square nut from Bag 3 and loosely attach it to the top right through-hole of the PrimoDrop-Main body, like shown in the picture. This will make it easier later on to mount the extruder on the Ender 3 extruder mount plate.


Items from Bag 1:

  • 1 x M5 lock nut

Items from Bag 2:

  • 1 x 688 ZZ ball bearing (diameter: 16 mm)

  • 1 x M5 Sleeve


Before inserting the 'Big-Driven-Gear', insert the last 688 ZZ bearing into the PolyDrive-Main body. After inserting the 'Big-Driven-Gear' screw the M5 Sleeve on the M5 bolt to secure the 688 ZZ bearing. Do not tighten the M5 Sleeve with a wrench otherwise the ball bearings will cant (jam). Just tighten the M5 Sleeve with your fingers.


Items from Bag 3:

  • 1 x M3 square nut

Insert the M3 square nut into the intended inlet of the 'Small-Drive-Gear'.


Items from Bag 3:

  • 1 x M3x8 grub screw

  • 1 x M3x8

  • 1 x M3 washer 


The 'Small-Drive-Gear' should be 1 mm away from the Nema 17 stepper motor. To achieve this use the M3 washer and place it close to the shaft of the stepper motor, then put the 'Small-Drive-Gear' on the shaft of the stepper motor until it touches the M3 washer. Lock the 'Small-Drive-Gear' in place by using the M3x8 grub screw.  Remove the M3 washer and use it with M3x8 screw to mount the stepper motor on the Ender 3 mounting plate.



Items from Bag 3:

  • 2 x M3x14

  • 2 x M3 washer

Remove the M3 square nut which was attached in STEP 5 and attach the PrimoDrop on the extruder mounting plate of the Ender 3. Screw in the remaining two M3 screws and M3 washer to the mounting plate. Slightly loosen all three screw so that the Primodrop can slide. Make sure there is good contact between the Small and Big Gear. Now tighten all three M3 screws.


Start your Ender 3 and go into the menu on the LCD screen. Go to:

Control > Motion

Scroll all the way down to 'Esteps/mm' and select it. Change the value to '348'. Press the scroll wheel to confirm the number. Then go back to the 'Control' menu and select 'Store Memory'.

That is it your are done.