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:
- 1, NEMA 17 stepper motors
- 1, 5mm to 8mm motor coupler (Use Part SAC1 and set to size 5mm Bore and 8mm Bore, You will need one more for the Z drive for a total of 3)
- 1, 8mm drive nut
- 2, 8mm 7" drive screw (Don't use the nut that comes with this screw)
- Z motor mount kit
- Z mounting bracket
Note that the 8mm drive nut is already attached to the Z-Carriage
The motor/bearing and spacers can be found here:
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
* These items are already attached to the Z-Carriage
The Z-Motor mount is made from 3.75" x 2.5" stock.
It can be made from 1/2" or 3/4" stock. 1/2" stock is too thin to use the 1/4" cross dowels for clamping so smaller slots are used instead. These small er slots and screw holes allow #10 1-1/2" machine screw to be used instead of the 1/4" bolt.
Cut out the Z motor template if you have not done so already. Carefully fold on the dotted line.
Tape the template to your stock and mark all your holes with a punch.
Two holes need to be drilled into the end of the stock. If you are using 1/2" thick stock use the holes closer to the fold on the template. If you are using 3/4" stock use the two holes closer to the edge of the template.
The large hole can be cut with a hole saw, forstner bit, Jig Saw, or scroll saw.
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.
There is a slight variation if you are using 1/2" stock.
Install two #10 hex nuts into the two slots shown. Then install a #10 hex nut then washer on a #10 1-1/2" machine screw.
Insert the screw into the hole you cut on the edge Z mount and thread it into the nut. The nut works just like the cross dowel.
Install Motor Drive Assembly
Slip the Z drive assembly over the two shafts as shown in Figure 9. Notice the orientation of the two clamp bolts. They should be facing the rear of the machine. 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” 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.
Here is a link to a coupler you can make with your 3D printer.
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.
The templates can be purchased here: