Sprinkler Cart - Axles
3 simple Aluminium parts need to be made for the sprinkler cart. These are made from 2x 10mm Alu round stock and 1x6mm Alu round stock
1x 10mm diameter x approx. 170mm long
1x 10mm diameter x approx. 130mm long
1x 6mm diameter x approx. 30mm long
Assemble the 6mm rod first. Drill and tap a hole for the small bevel gear. (Its best to test fit everything and mark the hole to be drilled.) Then screw the bevel gear to the 6mm round stock.
The holes are all pre-printed into the plastic parts.
Push the 6mm rod with the bevel gear attached through the bearing assembly until the bevel gear is flush with the Sprinkler cart body. Then push the 6mm Alu rod into the sprinkler disc.
With the 6mm rod in place now make the 10mm Alu Axle. This is made in 2 pieces with the 2 axles meeting (but not touching) on bearing 3.
First mark and drill and tap the hole for the rear wheel. Once the rear wheel is attached, push the 10mm rod through the wheel spacer, through the 2 bearings and into the sprinkler case.
Depending on which side you are making mark drill and tap holes for either the large bevel gear or the feeder screw.
The large bevel gear should fit snug against bearing 1 so that contact between the large bevel gear and small bevel gear is always made. As the 3D printed parts are already sized this fit is almost automatic.
The feeder screw should fit almost perfectly between bearings 3 and 4. This is also secured with an M3 bolt.
Drill and Tap?
Never drilled and tapped a hole before? Its really easy.
1. Drill a pilot hole smaller than the end tap size. For a 3mm tap you need a 2.5mm pilot hole. (on round stock sometimes its best to file a flat spot so the drill doesn't slip around on the round surface)
2. Use a 3mm tap to cut the threads in the hole.
3. Done already :)