In this installment we are going to install the Z drive assembly.  It’s a little different than the X and Y drives that you installed previously.  We will also be reinstalling the Z-carriage.


Z Drive Components

You will need the components shown in Figure 1 to complete the Z drive assembly. These consist of the following:

These consist of the following:

Note that the motor/bearing and spacers can be found here:

KReduCNC motor/bearing mounting kits



Z Drive Hardware

In addition to the drive components listed above, the following hardware fasteners will be needed for the assembly.

  • 4, #6-32 x 1-1/4" machine screws
  • 4, #6 washers
  • 4, #6 internal tooth lock washers
  • 4, #6-32 hex nuts
  • 2, 1/4-20 cross dowels
  • 2, 1/4-20 x 1-1/2" hex bolts
  • 2, 1/4-20 hex nuts
  • 2, 1/4" flat washers
  • 2, #10-24 x 1-1/4" machine screws
  • 2, #10 internal tooth lock washers
  • 2, #10-24 hex nuts
  • 4, #10 flat washers
  • 4, M3-.5 10mm cap screws
  • 4, #4 internal tooth lock washers



Assemble Motor Drive

To assemble the Z drive motor assembly, you first need to mount the motor to the two Z motor mount plates, as shown in Figure 2. The motor is secured with four M3-.5 x 10mm cap head screws and four #4 lock washers.

Next, install the motor coupler and drive screw, as shown in Figure 3. The 5mm end of the coupler is inserted on the motor and tightened.  The drive 7” screw is then inserted into the 8mm end of the coupler and the coupler tightened once again.

Slip the motor mounting bracket over the screw and coupler, as shown in Figure 4. Secure with the four 6-32 x 1-1/2” machine screws, lock washers, and nuts as shown.

Insert two cross dowels as shown in Figure 5. Secure them with two 1/4-20 x 1-1/2 hex bolts, washers, and nuts as shown.  Finger tighten only.  Note that you will have to remove the two #6 hex nuts and washers to insert the cross dowels.

Replace the two #6 hex nuts and washers. The final assembly should look like the one shown in Figure 6. 


Install Drive Nut

Take the Z-carriage plate and attach the Z drive nut as shown in Figure 7. Notice the orientation as the drive nut is attached to the back of the Z-carriage. Secure with two #10-24 x 1-1/4 machine screws, washers, lock washers, and hex nuts as shown.  Finger tighten only.

Secure the Z-carriage to the four trucks with the 16, 4mm x 16mm machine screws you removed earlier.  Remember to add the lock washer/washer combo to the screw, as shown in Figure 8.

Once the carriage plate is secured to the four trucks, move it all the way to the top and snug the upper screws. Next, move the carriage plate to the bottom and do the same with the lower screws. Once you are happy with the movement of the carriage, tighten all the screws. 


Install Motor Drive Assembly


Slip the Z drive assembly over the two shafts as shown in Figure 9.  Notice the orientation of the two 1/4" hex bolts.  The should be facing the rear. You may have to loosen the bolts a little so the assembly slides down over the shafts.

Slide the assembly all the way down until the bottom of the motor bracket is about 1/2” above the X carriage, as shown in Figure 10. Note that as you lower the shaft it will meet up with the drive nut.  Twist it into place.

Tighten the two bolts shown in Figure 11.  Then secure with the two nuts to keep them from loosening later.



This completes the KReduCNC Z drive assembly.  Leave the drive nut finger tight until we attach the electronics.  We will need them loose to make later adjustments.  Your CNC should look like the one shown here.


Drawing Files

Here is a link to a coupler you can make with your 3D printer.

Thingiverse 3D coupler

Thinigiverse simple coupler

Thingivers coupler


Mounting Bracket

Please note that these files are subject to change. You will need some sort of CAD software that can import eps or pdf files to use them.  They are raw 2D drawing files without annotations.