In this Installment we are going to install both the X and Y drive assemblies. The installation for each is nearly identical but you will have to remove your Z-carriage plate when installing the X drive assembly.
X and Y Drive Components
You will need the components shown in Figure 1 to complete the X and Y drive assembly. These consist of the following:
- 2, NEMA 17 stepper motors (You will need one more for the Z Drive for a total of 3)
- 2, 5mm to 8mm motor couplers (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)
- 2, 8mm drive nuts (You will need one more for the Z Drive)
- 2, 8mm 16" drive screws (Don't use the nut that comes with this screw)
- 2, Motor mount kits
- 2, Bearing mount kits
- 2, Drive nut spacer kits
- 2, 8mm bearings
Note that the motor/bearing and spacers can be found here:
Z Carriage Hardware
In addition to the drive components listed above, the following hardware fasteners will be needed for the assembly.
- 8 #6-32 x 3/4" machine screws
- 8 #6-32 x 1-1/4" machine screws
- 8 #6-32 x 1-1/2" machine screws
- 24 #10 washers
- 16 #6 washers
- 24 #6 internal tooth lock washers
- 24 #6-32 hex nuts
- 4, #10-24 x 2" machine screws
- 4 #10 internal tooth lock washers
- 4 #10-24 hex nuts
- 8 M3-.5 10mm cap screws (you will need 12 total)
- 8#4 internal tooth lock washers (you will need 12 total)
Bearing Mount Assembly
The first step is to assemble the two bearing mounts. Using Figure 2 as a guide, insert four of the #6 x 3/4" machine screws through the large plate. Add a small hole spacer and two large hole spacers to the screws. Next, insert the bearing into the pocket created by the two large hole spacers. With the bearing is in place, add the last small hole spacer to secure the bearing.
The last step is to add a #6 lock washer and #6 nut to each screw and tighten. Your final assembly will look like the one shown in Figure 3. You will need two bearing mounts.
Motor Drive Assembly
To assemble the motor drive assembly, you first need to mount the motor to the two main motor mount plates, as shown in Figure 4. The motor is secured with four M#-.5 x 10mm cap head screws and #4 lock washers.
Next, install the motor coupler and drive screw, as shown in Figure 5. The 5mm end of the coupler is inserted on the motor and tightened. The drive screw is then inserted into the 8mm end of the coupler and the coupler tightened once again.
Slip the motor mount spacer over the screw and coupler, as shown in Figure 6. This spacer will be secured in place once the assembly is attached to the frame.
The final assembly should look like the one shown in Figure 7. You will need to assemble two of these.
Bearing Mount Installation
Use four #6-32 x 1-1/4 machine screws to attach a bearing mount to the front of the CNC and secure each screw with a #10 washer, #6 washer, #6 lock washer, and #6-32 hex nut, as shown in Figure 8. Finger tighten only.
Repeat the process by installing the other bearing mount on the right side of the CNC, as shown in Figure 9.
Drive Nut Installation
Take a #10-24 x 2” machine screw and add a #10 washer. Slip them into the two large holes in the center of the Y-carriage plate, as shown in Figure 10.
From the underside of the carriage, add four of the drive nut spacers and the drive nut. Secure each screw with a #10 washer, #10 lock washer and a #10-24 hex nut, as shown in Figure 11. Finger tighten only. The drive nut should look like the one shown in Figure 12.
Repeat the process for the X-axis drive nut, as shown in Figure 13. Note that you will need to remove the Z-carriage plate. Place the removed Z-carriage and screws in a large freezer bag as you will not be reinstalling the plate until next month.
Motor Drive Installation
Start the X drive installation by inserting the drive assembly into the motor mount hole on the left side of the frame, as shown in Figure 14.
You will have to move the X-carriage far to the right and manually twist the drive screw into the X drive nut. Twist the drive screw until the motor mount is up against the frame and the drive screw goes through the x drive bearing, as shown in Figure 15.
Next, insert two #6-32 x 1-1/2” machine screws into the motor mount, as shown in Figure 16. Secure with a #10 washer, #6 washer, #6 lock washer, and a #6-32 hex nut, as shown in Figure 17. Finger tighten only.
Repeat the process with the Y drive (Figure 18). The only difference is the Y-carriage is moved towards the front of the machine.
Before closing I wanted to talk a little about the motor couplers. There are several sources for these. On my website I will give links for some commercial made couplers as well as some 3D printable ones if you have a 3D printer.
Please note that this build does not support helical or split couplers. They require drive screw clamps and stops in order to keep the drive screw from shifting. They are more suited to larger builds where there are greater load forces on the screws.
This completes the KReduCNC X and Y drive assemblies. Leave them finger tight until we attach the electronics. We will need them loose to make adjustments later. Your CNC should look like the one shown here.