Troubleshooting Tips

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Zen Toolworks CNC Machine Troubleshooting Tips

You have made the decision to purchase one of the Zen Toolworks kits to break into the world of CNC. You get the kit assembled, connected to your computer, powered up and nothing works or doesn't work like you expected! What do you do now? In this section I will attempt to cover some of the troubleshooting tips I have run across and guide you to a working machine so you can experience the world of CNC.

  • Please note: The following troubleshooting tips are directed towards those who are running the software package Mach 3 from and the TB6560 controller board from on one of the Zen ToolWorks CNC machines.
  • Thank you, johntech


Building the kit

  • Bearings
    In the first part of building the kits, you are required to install bearings into side pieces and bearing blocks. Getting the bearings installed correctly will help the X, Y and Z axis move smoothly. There are various ways to install them, a bench vice, drill press, large jaw plyers etc. The main thing here is to get the bearings installed straight without a lot of force. You should be able to start inserting them by hand and use the above mentioned tools to gently slide them in place. You want them to fit flush when seated into the hole. Remember to add the screw and washer in the appropriate hole next to the bearing to hold it in place. (DO NOT FORCE THE BEARINGS INTO THE MATERIAL!)
  • Anti-Backlash Nut
    The anti-backlash nut takes up the "play" between the nut and the lead screw. It needs to have a small gap (2mm) or (5/64") between the to two falans. If you make them too tight, there will be too much friction and put more load on motors. The Anti-backlash nuts also enable the movement of each axis via the leadscrew
  • Leadscrews
    Since the leadscrew controls the movement of each axis, you want to make sure they are clean and free of any damage. Damaged threads and filings will cause binding in the movement of the axis's. A dry lubricant can be applied to the leadscrew to reduce friction of the backlash nut. If none is available, then a few drops of light machine oil along different spots of the lead screw is ok. Wipe off any excess oil! No need to have oil dripping off it!!
  • Bearing Blocks
    Bearing blocks allow the leadscrew to turn freely in the frame pieces and guide the moving pieces of each axis via the linear bearings. After installing the guide rails and bearing blocks, make sure you turn the leadscrew from one end to the other by hand, checking for any binding in movement. You may need to loosen the mounting bolts and readjust the position to eliminate the bind or clean up the threads with a small triangle file if damaged. It is very important that the leadscrews move freely by hand as this will reduce the load on the motors!
  • Frame Alignment
    As you are putting the kit put together, you should get a carpenters square and square it up when tightening up the bolts and checking the leadscrews. This will ensure the cutting head is square to the table when mounted. ***NOTE*** The material that the kit is made of is extruded PVC meaning that the table and other pieces may not be perfectly flat! Adjust the best you can. Once you get everything the way you want, make sure all nuts and bolts are tight!

Computer Issues

  • Computers
    They come in all shapes and sizes today. The basic computer needed to run the Mach 3 software from ArtSoft is: 32-bit version of Windows 2000, Windows XP, Windows Vista, or Windows 7 Operating System (64-bit will not work), 1Ghz CPU, 512MB RAM using a Non-integrated Video Card with 32MB RAM and a parallel port, (noted from their website). Newer computers that don't have a printer port should be able to purchase an add on printer port card. As of this writing, using a USB to Printer cable will not work in running your control board. In helping you to troubleshoot a printer port issues, I have run across a small free program written by Fred Bulback at called PARMON. When run, it will provide valuable information about your printer port in real time. Very useful when setting up the Mach 3 or other controller software and checking the printer cable.
  • Printer Cable
    The printer cable needed for your computer to run your controller board is a 25 pin DB male to male feed through cable. It is just an extension of the printer port connector on your computer pin for pin. Things to look for when having problems:
  1. Check continuity from every pin on one end of the cable to the matching pin on the other end with a continuity probe or a multimeter set on the Ohms scale. Do this for every pin checking for a connection
  2. While checking for continuity, also note any pins that show No connection.
  3. Lastly check for shorts between pins.

   Should your continuity checks show pins not connected end to end or adjacent pins shorted together, I would suggest getting a different cable.

TB6560 Control Board

    This is the brain of the of the ZTW CNC kit. With the computer and software, this board makes it all happen. A few things on the board need be setup correctly for things to work.
  • Power Supplies
    There are 2 power supply connections that need to be made to the board: one is  7.0 - 9.0 volt DC for the onboard electronics and 12 volt DC for the motors. Click HERE  to see the connections. Check the voltages on these pins to verify you are reading between 7-9 volts and 12 volts respectively. Different people have connected power different ways and all have worked. You can connect one 12 volt supply to both the 12 & 7 volt inputs, you can connect a series of diodes from the 12 volt input to the 7-9 volt input to drop the voltage down closer to 7 - 9 volts or add in a M7809 voltage regulator from the 12 volt supply to the 7-9 volt input.
  • Motor Connections
    To the left of those connectors you will see 3 separate connectors marked A A- B B-. Click HERE to verify the correct motor wiring for those connectors. If you are using the ZTW motors with the RED, BLUE, GREEN and BLACK wires you should be able to connect them as follows: RED to A, BLUE to A--, GREEN to B and BLACK to B--.
  • DIP Switch Settings
    There is a 2 section DIP switch and a 4 section DIP switch SET for each axis on the board that needs to be set correctly . Click HERE  and scroll down to see the correct the switch settings for each switch set.

Software Issues

For this troubleshooting section, I am using Mach 3 from Artsoft, the TB6560 control board, running Windows XP on a 1.2 gig processor, 1 gig of memory, 160 gig hard drive and an onboard printer port with a 1 to 1 printer cable. The following settings are from my computer and software as mentioned above running on a 3 Axis ZEN ToolWorks 12x12 machine:

  • From the Config menu for Ports and Pins here are my settings for the Motor Output
  • From the Config menu for Ports and Pins here are my settings for the Output Signals
  • From the Config menu for Ports and Pins here are my settings for the Motor Tuning 
  • From the Config menu for Ports and Pins here are my settings for the Input Signals ****
  • Limit Switches
    • **** Depending how you run your machine, you can omit the Limit and E-Stop switchs and just set your "0" or "Home" positions manually. To do so, in the Input Signals screen, set all the "Pin Number" settings to 0 or zero. This will disable all Limit switches and the "EStop" button on the screen so all you have to do is click it to reset it. 
      NOTE: You may want to have an E-Stop switch ...just in case!!
    • This is how I have my Limit and E-Stop switches wired to the TB6560 controller to match my Input Signals settings in Mach 3. This will allow you to click the REF ALL HOME button in Mach 3 and all the axis's will move to their HOME positions and stop.
    • If you are going to use Limit Switches, you should set up  Homing /Limits from the Config menu. This will setup the Soft Min and Soft Max distance that your table can move.
    • To help you configure the switch settings in Mach 3, they have provided an automated way of configuring them in the software. From the Config menu goto Ports and Pins and click on the Advanced button. This will take you to the Automated screen. Select the switch you want setup from the pulldown box and click the AutoSet button. Now trip the switch asociated with the selected switch and it is automatically setup for you in the software. Continue with the rest of your switches and you won't have to guess how to set them up.
    • NOTE !  Once you have all your settings working like you want, goto the Config menu and select SAVE SETTINGS.

For those who want to use the Limit and EStop switches, this is how I have my machine wired to use the Home/-- Limit switch combination and the ++ Limit switch here.   

While in the Mach 3 software, to aid in troubleshooting your machine there is a Diagnostic screen which helps to see if motors are enabled, Home and Limit switches are working, etc. 


Misc Help

  • Machine Movement

   Once you have your machine setup  and you want to check if the axis's are moving in the correct directions, remember, all movement is referenced to the spindle.

   To check the movement of the axis's, view your machine overhead with the X axis away from you.

  • Pressing the < (left arrow) the X axis should move to the Left while pressing the > (right arrow) the X axis should move to the Right.
  • Pressing the ^ (up arrow) the Y TABLE should move toward the front of the machine (simulating the spindle moving toward the back of the machine).
  • Pressing the v (down arrow) the Y TABLE should move toward the back of the machine (simulating the spindle moving toward the front of the machine).
  • Pressing the Page Up button, the Z axis should move upward away from the table and Page Down move down towards  the table.

   For general references the FRONT- LEFT corner of the table is location  X0,Y0    *** Location X0,Y0 can be set anywhere on the on the table ***

Here is a PDF that explains machine movement visually! Thanks Ken!!


Machine Upgrades

  • Auto Zero your tool bit
    by johntech » Tue Mar 06, 2012 8:56 pm

Hi guys

Here is a neat little setup to allow you to zero your tool to the material before you start cutting. Here is a routine I found on CNCZONE that will work with this setup. ... _zero.html.

  • Nice Addon Screen for Mach 3 Users
    by johntech » Sat Feb 25, 2012 6:40 am

Hi Guys

I just purchased a very nice addon screen for Mach 3 users called 2010 Screenset. It has a couple of auto zeroing routines and a auto probing routine in it plus many other features I'm still learning to use. The price is only $20 and can be found at I sent my order in via PayPal and had the files within 1/2 an hour. With my external "zeroing plate" setup the bit is automatically set to just touch the material when ready to mill. All my guessing at where to set the height is gone. I am not associated with the developer just a happy user.


Controlling the Spindle from Mach 3
by johntech » Sun May 20, 2012 9:26 pm

I designed a circuit for controlling the Spindle motor via Mach 3. Here you will find the posts I made while designing the circuitry, information on creating a Break Out Board, the final schematic and a Word file discribing how it works and how to set it up in Mach 3.



  • An Inexpensive 4th (Rotary) Axis
    by Sparky » Tue May 31, 2011 6:09 pm
    An Inexpensive 4th (Rotary) Axis with all the info to build and add on to the your machine provided by Sparky form the ZTW forum.
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