Appendix G: Instructions for Construction

The following table lists the required materials and their quantities. Refer to Appendix F: Bill of Materials for links to products and prices. 

Additionally, the following tools are required in constructing this device:

• Soldering iron and solder

• Lathe 

• Vertical band saw 

• Horizontal band saw

• Box and pan brake 

• Handheld drill with assorted bits

• Drill press 

• Dremel 

Several components must be modified ahead of time prior to assembly. This section outlines the steps in preparing the wheels and motor. 

Both of the wheels must have a groove cut in the middle to ensure the oxygen tubing does not slip out during retraction. The wheel is on a bearing so a jig must be fashioned to cut a groove with the lathe. 

To cut the groove, follow these steps:

1. The wheel must be stationary for the lathing process, so you must first obtain a threaded rod, 2 washers, and two nuts to create a temporary mechanism that will keep the wheel from turning on the bearing. 

2. Place the threaded rod in the wheel and fasten the washers and nuts on either side of the wheel to secure the mechanism. 

3. Fasten the wheel mechanism to the spindle of the lathe and place a facing tool on the tool post. 

4. Since the wheels are not exactly circular, use the facing tool to shave off a small bit of the wheel to ensure it is the same diameter all the way around.

5. Next, replace the facing tool with a round nose tool with the diameter of the tubing (0.24 inches). 

6. Now, use the lathe to position this tool at the center of the wheel and cut a groove of the custom depth of 0.12 inches. 

7. Repeat steps 1-6 with the second wheel.

Soldering 

The motor has to be wired to the switch and power supply in a way where the switch can reverse 

the direction of the motor. Use the diagrams below as reference (Figures G1 and G2).

Since the design requires the motor to be sideways, a bracket must be fashioned to mount the motor in the required position as shown in Figure G3. This will attach to the motor bracket that originally came with the motor.

1. Cut a piece of 14 to 18 gauge aluminum to the width of the existing motor mount and a length of 1.5 inches longer than the motor using a vertical bandsaw. 

2. Use a box and pan brake to fold the aluminum as seen in the figure such that there is enough room for the motor to sit. 

3. Mark the holes needed to attach the existing motor mount to the new bracket with Sharpie then drill them out on the drill press. 

4. Use nuts and bolts to attach the two brackets together. 

The motor shaft is much smaller than the center hole in the wheel. Thus, to mount the wheel, a larger shaft must be machined that will fit on top of the motor shaft and through the wheel. 

1. Obtain an aluminum rod that is greater than the diameter of the inside of the wheel.

2. Use the horizontal bandsaw to cut it to about 4 inches. 

3. Fasten the metal rod piece to the spindle of the lathe and place a facing tool on the tool post. 

4. Use the facing tool to shave off the edges of the metal rod such that it reaches the dimensions of the diameter inside of the wheel. 

5.  Next place a drill bit of .23 inches into the tailstock and use the lathe to drill a .31 depth hole in the center of the metal rod piece. 

6. Find a M4 set screw no longer than 10 mm.

7. Using a drill press, drill and tap a hole of the appropriate size into the side of the metal rod, intersecting the central hole.

8. Mount the metal rod on the motor, add the set screw to the tapped hole, and screw until tightly secured.

1. In constructing the free axis, find a threaded bolt that fits through the wheel bearing and is about 10 inches long. 

2. Use 2 sets of 2 nuts above and below the wheel to lock it in place at the desired position on the bolt. 

3. Once the other wheel is mounted on the motor, cut the bolt to the appropriate length to match the height of the motorized wheel. 

4. Any fine adjustments can be made by altering the height of the wheel on the bolt by unscrewing then locking the nuts in place.

With all the materials prepared, assembly can begin on mounting the components to the container.

With the motor and wheels prepared, the Oximatic is ready to be assembled onto a slab of wood roughly half an inch thick. 

1. Position the two wheels on the board so that the wheels are touching as shown in Figure G4.

2.  Mark the spots to screw in the motorized wheel and the free axis, then drill them with a bit slightly smaller than the size of the screw.

3.  Screw in both the motorized wheel and free axis. Epoxy on the free axis is recommended in order to ensure a tight, snug fit.

At this point, once the epoxy is dry, the wooden board can be mounted inside the container. 

1. I the four corners of the wooden slab, drill four holes slightly smaller than the diameter of four screws.

2. Screw the four screws with washers into the four holes. 

3. Place the slab inside the container and mark on the container walls where the screws touch. 

4. Drill a hole the size of the screws in these locations.

5. Push the slab so that the screws poke through the container, then screw on a nut firmly on the four screws as shown in Figure G5.

6. Use a dremel to cut the screws flush with the exterior of the container.

1. Find a suitable location for the switch on the outside of the container. 

2. Drill a hole here with a bit the size of the switch housing.

3. Unscrew the top portion of the switch.

4. Fit the switch through the drilled hole.

5. Screw the top portion back onto the switch snugly so that the switch does not wiggle around.

1. Drill two holes on opposite sides of the container where the tubing will enter and exit. These holes should be the same size as the plastic hose connectors. 

2. Mix a batch of epoxy. 

3. Epoxy the two connectors into the two drilled holes. 

4. Wait 3-5 minutes for the epoxy to set.