This section covers installing the belting.
9mm Belt and Motor Kit
3GT Belting 9mm (4 meters)
Belt Clip 9mm
Belt Sleeve
Core Components Kit
M5x25mm Low Profile Socket Head Screw
M5 Flat Washer
M5x8mm Button Head Screw
M5 Nylon Lock Nut
X-Carve Kits shipped before April 2022 will include a different M5x25mm screw. Instructions for both screws (button-head and low-profile) are provided.

Prepare Belts and Hardware

Start by cutting the 4 meter length of belting into 3 equal sections. Each piece of belting should be just long enough to reach from corner to corner on the waste board, as shown below.
Each axis (X, Y1, and Y2) uses the same hardware and quantity. Lay out the belts and hardware listed above so each axis is ready for assembly. X-Carve Kits shipped after April 2022 will have a slightly different M5x25mm screw than what is shown below.
If you cut the belting incorrectly, you can find another 4 meter length of Open-Ended 9mm Belting in the Spare Parts Kit.

Install Belts on Pulley Assemblies

On the Y1 axis, route the belt (teeth side down) under the smooth idler, over the motor pulley, and under the other smooth idler. Lay the rest of the belt across the Y-axis such that there is a bit of overlap on each side. Repeat this for the Y2 axis.
Now you will install the belt on the X-axis.
The X-axis is by far the trickiest of the three. You won't be able to route the belt over the pulley by going in from the side of the x-carriage, so you'll need to go through the hole in the top. This works best if both ends are first curled before placing them through the top hole.
Feed one curled belt end between the pulley and smooth idler, and instead of forcing the belt through, slowly move the X-Carriage in the opposite direction to help reveal the end of the belt. Once revealed, grab the belt and pull it further through. Repeat this process with the other end of the belt, and center the belt such that there is overlap on each side of the X-axis.
Adjust the belt as needed so that each end reaches the ends of the Gantry (Wide Makerslide).
If you’re having trouble with the X-axis belting, check out this Community Forum post: X-axis belt installation.

Attach Belt Clips and Sleeves

Each end of the belt has a belt sleeve and is secured to the machine by a belt clip. Take one end of the belt and add one of the belt sleeves, small end first (wide end pointing towards the nearest end of the belt, with the tapered end closer to the center of the belt).
There is a very small difference in the opening size for the ends of the belt sleeve. The small notch pictured below indicates the larger opening on the belt sleeve. For the following steps, we will be inserting the smaller end (no notch) onto the belt first.
Route the belt through the sleeve (as pictured below), into the clip, and through the remaining slot. Push the end of the belt through the wide end of the belt sleeve to lock the teeth in place. Try to leave at least 2 inches of excess belting on each end, to ensure that there is enough length available for the teeth to lock into each other. Repeat this process for each end of the belts on the Y-axes and the X-axis.
Once all three sections of belting have the clip and sleeve attached to both ends, locate your M5x25mm Low Profile Socket Head Screws (or standard for pre-April 2022 X-Carves). Each section of belting only requires one tensioning screw).
Screw Placement: When facing the machine (X-Carve label on gantry facing you, sideboard to the left of the machine), the Y-axes should have the M5x25mm tensioning screw towards the back, and the X-axis should have the tensioning screw towards the right-hand side of the Wide Makerslide
Insert the M5x25mm screw from the inside of the clip into the hole marked with the orange arrow below, so that the post of the screw sticks out from the clip and the head of the screw lies on the inside of the bend.
Next, place an M5x8mm button head cap screw through the belt clip into the remaining circular hole, on the same face as the belt loop. Placing both screws through the holes prior to threading them into their respective locations will make it easier to access the screw heads with a hex key.
Note: If you have an X-Carve Kit that was shipped before April 2022, this process may require additional patience. If you're having trouble with the belt clip, try installing the tensioning screw first (M5 x25mm). With your thumb at the end, use an allen key to screw in the M5 x 8mm button head cap screw. It will require a bit of force. Try not to bend the belt clips during this step.
Once the screws are inserted into the clip, thread the M5x8mm button head cap screw into one of the two pre-assembly t-slot nuts that were inserted into the X and Y-axes in a previous step. You may need to slide the t-slot nuts along the extrusion channel to the appropriate location. Then, place the M5x25mm Low Profile Socket Head Screw through the hole of the rear riser plate (Gantry Side Plate [Right] for X-axis tensioning screw), add an M5 washer, and hand thread an M5 nylon lock nut just enough so that it is secure.
Once the belt clips with tensioning screws have been secured to the rear sides of the Y-axes and the right side of the X-Axis, you will secure the other end of each belt.
Start with the unsecured end of the Y-axis belts. Remove as much slack from the belt as possible by pulling the excess through the belt clips and then hold the belt clip flush with the front end plate. Limiting the slack in the belt will make tensioning easier.
Place an M5x8mm button head screw through the belt clip (next to the belt loop, as shown below) and tighten it to the other pre-assembly t-slot nut we installed earlier. Secure the screw and nut loosely with a 3mm hex key.
Repeat this step on the remaining belt clips, securing them with an M5x8mm button head screw threaded into the M5 pre-assembly t-slot nut inserted into the extrusion channel, with the end of the belt clip flush with the end plate (or side plate, for the X-axis).

Belt Tension

It is important to not waste any threads on your tensioning screw, since you will need to tighten the screw a bit to achieve the proper tension. The best way to do this is by starting with some* (*read: "as much as possible") tension in your belt. You should be able to pull the front belt clips flush to the end plates without the belt fighting you, but you really do not want any more belt-length between the clips than what is required. If you start with tension already in your belt, you won't have to deal with undoing the tensioning screw and feeding more belt through the belt clip; essentially redoing all of the work you just did.
To begin adjusting the tension of the belts, pull any excess length through the belt clips, the excess can be trimmed later. Then, place your hex key in the head of the M5x8mm button head cap screw on the front clip (without the tensioning screw) and pull towards the front of the machine making the belt tight. With the clip flush to the end/side plate, tighten the button head cap screw in place.
Then, go back to the tensioning screws on the opposite end and start tightening down the M5 nylon locking nut until you have reached the appropriate tension. There are more specific tension-calibration tips in the Calibration and Maintenance section of the instructions. For now, though, we are looking for the belts to make an audible noise when plucked.
Once you achieve that tone (similar to a bass string on a guitar), tighten down the remaining M5x8mm button head cap screw on the rear (or right side, for the X-axis) belt clip to secure the assembly in place. Ensure that all three belts are secured tightly on both ends and that they are tensioned properly before carving.
After installing, you may cut off excess belting at the end. You may want to leave about 2 inches behind for adjustments.
For more information on tensioning your belts or to check that your V-wheels are properly tensioned, you can use the Calibration and Maintenance guide.