Step 7: Mount Y Carriage



Mounting the Y Carriage Once the Y carriage is assembled, it needs to be mounted on to the machine. The double wingnut/spring assembly on the threaded rod is what reduces backlash in the system. This same assembly is also used in the X and Z carriages.

Step 1: Take the longest of the three pieces of threaded rod and insert one end through the MIDDLE hole of the Y carriage assembly. Make the wingnut/spring assembly pictured by first threaded one of the wingnuts on the rod with the wings facing OUT. Next, place one of the springs over the rod and then thread a second wingnut onto the rod with wings facing IN, making a spring sandwich between the two wingnuts. The sandwich should be tight enough so that the two wingnuts almost (but don't) touch each other. Note the location of the wingnut sandwich: it should be located INSIDE the carriage base assembly (between the two clear plastic base pieces)

Step 2: Included in the kit are three white HDPE blocks, one of which is shorter than the other two. The short one is reserved for the Z carriage, so use one of the longer ones for this axis. One of the two longer HDPE blocks may have been sanded down to reduce its thickness. For this carriage, use the block that has NOT been sanded down. Place the white plastic HDPE block under the wingnut sandwich. There is a chanel machined into the block to accommodate the radius of the wingnuts.

Step 3: One of the wingnuts will be mounted to the plastic block with two screws. Without affixing the HDPE block to the wood yet, drill 1/8" holes in both wings (and into the block) of the wingnut that will be CLOSER to the motor (front) side of the machine. Then using two of the block mounting screws provided (in the bag of 6 silver screws), screw BOTH wings of that single wingnut onto the plastic block, while keeping the rod perpendicular to the block. The second wingnut should be left unscrewed, but it will be unable to unthread itself because the block is inhibiting its movement.

Step 4: You should now have your wingnut sandwich affixed to the HDPE block, screwed on to the threaded rod, and located inside the Y carriage base assembly. You can hand-turn the rod to move the position of your wingnuts on the rod. Note that the HDPE block is still free and will be affixed to the underside of the Y carriage a little later. Insert one of the three identical plastic flanges into the center hole on the back steel beam. This flange is where the free end of the threaded rod will rest (opposite the motor side). The flange can be glued in place if there is not enough friction to hold it into the steel beam.

Now fit the Y carriage assembly into the steel frame base, guiding the threaded rod through the center holes in the front and back fo the base.



Step 5: Begin mounting the carriage to the two precision rods: take the 18" pair of rods (wipe off any oil residue with a clean cotton rag) and carefully work them through the grommets at the front of the steel base and then through the bearings in the Y carriage. Do not use excessive force or hammer the rods into place; instead you can use a twisting motion to work them through the grommets. Finally, they should go through the rear grommets in the steel base.

Step 6: Affix the Y carrage wood table to the HDPE block/threaded rod assembly. Line up the plastic block under the table with the two laser-cut holes that are located in the central part of the wood table. Using two screws, affix the Y table to the HDPE block, mounting the screws from the top of the table down into the block. Make sure the threaded rod is in proper alignment before screwing into the block. Step 7: The shaft of the motor that moves the Y axis will be connected to the threaded rod using a piece of vinyl tubing as a coupler. The reason vinyl tubing is used is because it provides a stable coupler mechanism that has the capability of breaking away if one of the carriages was crashed into the side. That way, it can serve as the weakest link that can fail before other parts that could potentially cause greater damage in the event of machine error.

Mounting the vinyl coupling to the threaded rod requires that you heat it first to make it more pliable. That can be done with a heat gun, hair dryer, or even a cup of boiled water. We've had most success with a heat gun. ''Be cautious when using heat in these next steps. Hold the piece of vinyl tubing with pliers or another tool that will allow you to keep your hands away from the heat source. ''

The kit includes at least 3 pieces of clear vinyl tubing. The goal is to get roughly half of the piece on the threaded rod, and then the other half of the piece on the motor shaft. To get the piece on the threaded rod, heat up the vinyl (preferably just one end, if using a heat gun, being careful not to scorch or totally melt the piece) until a little more pliable. Then, working quickly, twist the heated end over the exposed end of the threaded rod. It may take a few tries to get it on. Try twisting it over the rod to get it mounted. You should be able to eventually get about half the vinyl piece onto the threaded rod, as depicted. Next apply the same technique to get the exposed half of the vinyl tubing to mount onto the Y motor shaft. (All three motors are identical, the designation of X, Y, and Z motors is determined by how they are wired.) When done properly, the ends of the threaded rod and motor shaft should meet inside the vinyl tubing.

Step 7: Mount the Y axis motor. The motor connects to the steel frame using two screws through the two small holes in the steel, then into the front of the motor itself. In the front beam of the steel base, there should be two small (1/8") holes in front, and two larger (1/4") holes on the opposite side of the beam. The M3 screws to mount the motor will have to go through the 1/8" hole and then through stand-offs and into the motor, so the 1/4" holes are there to allow access to the 1/8" holes.

Getting the screw through the 1/8" hole may take some patience. You can try magnetizing (running a magnet over) the end of your hex wrench so that the screw clings to it, allowing you to fish it through the hole. Get both screws through the holes, then place two white plastic stand-offs and two M3 washers over the exposed ends of the screws, and finally screw them into two of the four holes on the front of the motor until secure. For the two motor holes to line up properly, rotate the motor 45 degrees.