K8200 my Printer modifications, Milling and Drilling CNC

Hello everybody.

I had done some good modifications on my 3D-Printer (K8200), like working LCD Display with SD-Card and Encoder.
I change to trapezoidal spindle and also added a second one on the right side of the printer.
Firmware was changed to repetier 0.83, there i have updated several things so that the controller board can work.
I also added a menue point that i can switch a LED Strip on and off, over the controller and display.

Best regards,

Look terrific.
great job

Very nice job!!

Could you post a close-up picture of the right carriage (and perhaps the STL file)?
Did you plug the 2 motors to the same controller?

Could you post some pictures of your print outs?

Nice! In addition to the previous posters I have some more questions.

  • What trapezoid did you use?
  • Did you have to modify the Arduino code because of the trapezoid?

Your design looks like the other design here :
I was wondering whether the stepper motors in these dual Z-axis designs will always stay in sync.
I would not assume they will do so which can result in torsion and so.
Any thought of people in the forum about that?


Hello thank you for all remarks.

Yes i have both Z-Motors on the same controller, you have to use a additional heatsink on the Stepper IC and it would be
better when you use also a fan. I have heatsinks on each Stepper controller assembled.
Now i have to print a new case for the electronic with a cooling fan inside.

For the sync of both Z-axis, this is not a problem because they are on the same controller.
The only thing you have to do is measuring the alu-profil height (where the Extruder is mounted) on the left and the right side.
Also you have to check that both spindle are going free from beginnig to the end. Otherwise maybe one of the motor could lose some steps.

I had to modify the firmware because i use TR8x1,5 Spindle. The old M8 Spindle is 1,25 per rotation.



i also updated the heatbed with additional powersupply. (24V/6A)
I designed a PCB and have printed a case for it.
I will post it as soon as possible.

Best regards,

Here are some additional pic’s.

The right side Trapezoid.

The Headbed Schematic.

There i used the same components as on the Printer mainboard.

The PCB-Test.

The Headbed Case.

Hope you enjoy :slight_smile:

Best regards,

Nice design. Where did you purchase the rods?
And what kind of guide did you use? On the picture it looks trapezoidal.

I purchased all on eb… :slight_smile:
Yes it’s trapezoidal.


Im only asking the question but what improvements have you seen using the twin Z axis motors?

Im strugling to get my mind around it, to deem it worthwhile? nethertheless great job.

Just building mine but I noticed that the z-axis tends to stutter a tad when only driven on one side. Above mods should solve that completely.

Simple Answer why i have added a second Trapezoid on the right side.

I have seen that the Z-Axis (Aluprofil where Hotend is mounted) is wobbling when the
printer desk is moving fast. Mostly when i print somthing really thin (approx. 2mm) and the
Printer is working on the infill. Also the original 8mm Bearing on the right side is not so good.
You can move the Profil not only up and down (only without second Spindle), also to the front- and backside a little bit.
This are all bad things and you can see it in your printouts.

This upgrade was not really expensive, but it is a good investment when you want better printouts.
Everyone should make this upgrade and you will be very happy with your K8200. :slight_smile:

Best regards,

i´ve seen your Rebuild to give the K8200 a second Z-axis motor. It looks truly very impressively.
Maybe you can give us a Construction manual, so i can give this to my K8200 too?
And maybe a list where to buy these stuff?
Best Regards


Probably you had to change the firmware, because of the new Tr8 spindle.
I’m new and can you tell me what you have done?


you have to edit the file: configuration.h

#define DEFAULT_AXIS_STEPS_PER_UNIT {64.25,64.25,3200/1.5,600} // default steps per unit for ultimaker Z-Achse 2560 for metric threads, pitch 1,25

the trapezoidal screw that I use is TR8x1,5.
forum.velleman.eu/viewtopic.php? … 886#p41185

You can find the finished file here:


Nice bracket for the LCD panel.

Where you find the stl file or did you designed it?


Could you help me?
I tried to get the LCD board from open-electronics for the 3Drag to work, but just got it light up with no text coming on.
Uploaded the lastest firmware from Velleman (With the lcd section added) but still no luck.
Do you have a idiots guide to getting it working?
Thank you for any help you can give.
Best regards

how to connect up your LCd to have information this


Hello @ cheezy,
i don’t use the LCD from open-electronics, but i think it’s the same.
I have made an additional PCB for the correct pinout.
Can you post your pin configuration from the firmware?

Best regards,