CAD

Instructions: 

Start by creating a square out of four 127 bars. Attach the square by using four angle brackets in each corner. The angle brackets are secured by inserting T nuts into the bars and bolting the brackets using M5x10 bolts onto the T nut. After completing one square, create a second square using the remaining 127 bars.

Next, link the two squares together using the 300 mm bars. This is done by aligning the two squares to one another and attaching a 300 mm bar to the outer edges of both squares. Use an angle bracket on the inner rim to secure the bar into place. Repeat this process until the frame is a rectangular box.

To create the legs, grab three 300 mm bars. Attach the bars using angle brackets to yield a ‘U-shape’. Once completed, repeat the process a second time. Afterwards, attach the rectangular box to the center of the ‘U’ using angle brackets. Do this for both sides to complete the frame.

Step 2: Pulley and Belt

Required Components:

• • 20x20 Aluminum Extrusion 300mm x2

  • Angle brackets x24

  • M5 T Nut x24

  • M5x10 Bolts x24

  • M5x20 bolts x24

  • Shaft x6

  • Pulleys x 12

  • Bearing x 12

  • Shaft Collar x12

  • Belt

Instructions: 

Begin by attaching four angle brackets to the top side of the bottom row. Align the brackets such that they are are barely wider than the belt. After this, grab two angle brackets and a 300 mm bar. Attach the bar such that that the angle bracket is parallel with the previously attached brackets from earlier. Once the bar is attached, place four brackets along the top of the bar such that they are [X] inches apart from the center. Now, attach four angle brackets to the bottom side of the top bar. These angle brackets should be parallel to the angle brackets on the bottom row. Complete this for both sides of the device.

Once the angle brackets are secure, attach bearings to each pair of two brackets using M520 bolts. After securing the bearings, insert the shaft into one of the bearings. While sliding it through, add on a shaft collar, the two pieces of the pulley, and another shaft coupler. Make sure the belt is around the shaft. Once all these pieces are in place, insert the other end of the shaft into the adjacent bracket. Secure the couplers and pulleys such that the belt fits and is in the center of the shaft. Do this for all six shafts.

Step 3: Brush Holders

Required components:

• • 3D printed brush holder piece x3

  • Steel wire

  • Brush x3

Instructions:

Firstly, the brush bristles must be removed from the brush. After removing the bristles from the brush, the bristles are to be inserted in the middle of the brush holder. Poke a steel wire through the two holes on the brush holder and pierce through the brush to reach the other side. Tie up the wire on the other end to secure the brush in place.

Once that is completed, insert two steel wires into the bottom holes of the brush holder. Twist the wires around the timing belt and secure it. Repeat this process for the other two brush holders. Make sure that the three brush holders are separated an equal distance from one another.

Step 4: Motor

The motor is mounted using a 3D printed motor mount which makes use of the same T-nuts used to mount the angle brackets. The mount is attached to the motor on one side and the frame on the other side. The shaft can be screwed in using an allen key through the slots in the motor mount.

Step 5: Case

Required components:

• • Plywood

  • Steel angle bracket x4

  • Screws

Instructions:

Ideally this should not need replacement, but may be necessary if the case is dropped or cracks.

Cut the plywood to the dimensions specified in the CAD files, there should be four wall pieces and one cover piece. The two larger wall pieces running parallel to the belt should match the 300 x 127 mm aluminum bars in the framing step, and the two smaller square wall pieces should match the 127 x 127 bars. There are no specific requirements for the size of the angle bracket or the screw. The angle bracket should be large enough to connect the exteriors of the plywood. Connect the plywood to the angle bracket with screws.

One wall of the plywood will need to be cut to allow the motor mount to pass through. This step is relatively difficult by hand, and will likely require the use of power tools or machining.

CAD images of finished product without casing:

CAD of finished product with casing (without electronics other than motor)