Taz 2.1 Lead Screw Update

I have a couple questions regarding this change…

I have the new Taz 4 style hardware installed on the Z axis. Is the only firmware change needed the z steps per mm from 800 to 1600? Is there something else?

Secondly, when I attempt to upload the firmware with modified settings, they don’t seem to save on the Rambo. The sketch compiles and uploads, the rambo restarts but the old settings still exist following the printer power cycle.

I am running Windows 8.1 with Arduino 1.0.5. The computer recognizes the rambo board on port 8. Everything seems happy but the settings do not stick.

Any ideas out there??


Further digging resulted in finding a note in the forums that Lulzbot changed microstepping settings on the Taz 4. That seems to be why the T4 firmware calls for 1600 steps per mm on z. 400 seems to be correct for my 2.1. The old threaded rods had a 1 mm pitch and ran at 800 steps per mm. So, 400 for the 2 mm pitch lead screws makes sense.

I am still having problems with the Rambo flashing if anyone has a suggestion, I would appreciate it.

We have precompiled firmware files for updating your firmware though Cura here: http://devel.lulzbot.com/TAZ/Holly/software/2014Q3_rB/Marlin/

  • Save the file called: Marlin.cpp.hex
  • Power on the printer and connect through USB
  • Launch Cura
  • Select Machine > Install custom firmware
  • Navigate to the firmware hex file downloaded earlier and select it.
  • Your firmware will be flashed
  • Unplug and power cycle the printer.
  • Update your extruder steps per unit through the Graphical LCD controller or through the M92 E-__ EEPROM commands, like so:
M92 E850

then save the setting:


Verify updated esteps are saved:


If you still prefer to use the Arduino IDE:
Turn on Verbose output to get a better idea as to what’s going on:
Arduino IDE > File > Preferences > Show verbose output during: Compilation & Upload

If your local Arduino installation can successfully compile the firmware, make sure your printer is powered on prior to the upload process. If your firmware does not compile, you may not have the libraries merged correctly.

If you still have difficulty send an email with any error messages to Support@LulzBot.com and we’ll help how we can.

Thank you. I will give this a try tonight.

This question is for anyone that has the Taz 4+ lead screw setup.

I have updated my older Taz with Taz 4 parts. The screws are from Misumi and other hardware is per the Taz 4 BOM.

This update eliminated Z backlash. I am able to get my first layer perfect.

Unfortunately, it has caused a new problem that actually didn’t exist with the old threaded rod set up… Z wobble! It is very slight but it is visible on my parts. If I move the Z axis up or down, I can see the wobble in the X ends.

Have any of you experienced this? Does this mean I have lead screws that are not straight? Is this a problem that can be tuned out?

I have loosened all the z axis parts and moved z in an attempt to align everything. That did remove some binding I was having but the z wobble persists.

Any ideas out there?

You have bent threaded rods! I have a Mini Taz printer I am working on to replace two bent Z threaded rods on right now.


I can’t see what else it would be… I guess I will call Misumi tomorrow.