Build a Delta 3D Printer - Setting up the towers

The towers will be the vertical elements through which the carriages slide up and down, we’ll use the three 1 meter 2020 aluminum extrusion segments.
Let’s prepare our carriages by adding the wheels, we’ll use the 40mm M5 bolts to fix the plastic wheels to the carriages. Do not tighten them all the way, we want to slide them into the towers before that. Add a 20mm M3 bolt to the socket on the top of the carriage, these bolts will be interacting with the switch on the endstops to tell the printer when it has reached home but we’ll get into that later.
Slide the carriage through the 1 meter aluminum extrusion and tighten the bolts till the carriage has a firm grip but is also movable, if the wheel bolts are tightened too far the motor will overheat and cause a layer shift, if they are too loose they will jitter between each movement during the print causing a shaky and slanted print. Repeat this process for the three towers.
Now let’s move on to the endstop and endstop holders, these will be our go to element for calibration. Failure to set up these endstop holders correctly might result in infinite homing, meaning your printer won’t know when to stop when looking for the endstop switch and will keep moving the motors till it hits something or breaks away from the tower. We don’t want this to happen. We’ll use two sets of 10 M3 bolts to fix the endstop to the endstop holder and one set of M4 bolt, washer and nut for the outside of the endstop holder, this M4 bolts will keep the endstop holder fixed to the tower and will be used for calibration.
Slide the endstop holder through the tower with the endstop facing the same direction as the carriage, we can now test the positioning of the endstop by moving the carriage up till the M3 bolt head touches the metal switch. Repeat this process for the three endstop holders.
Now we’ll add the arms to the carriages, we’ll use 5 M3 20mm bolts, 1 M3 25mm bolt and 6 M3 hexagonal nuts. Slide the M3 bolt through the ball head buckles and in through the carriage side openings, place an M3 hexagonal nut on the inside and fasten the bolt till it bites the nut and is tightened correctly, the grip should be firm and there should be no play on the ball head buckles. Add the cable holder for the right side of the X carriage and use an M3 25mm bolt instead of a 20mm. Now we’re ready for placing the towers in the base.