Differential-drive chassis plate: parametric template

Parameters

Open in the editor opens the design with these defaults; change them afterwards in Modify › Parameters, and everything that depends on them follows. Opened from the editor’s template library instead (New ▾ › New from template…), the template asks for its values first and checks them against these ranges and against each other, and Copy link gives an address that opens it with your values.

Name	What it sets	Default	Range
`diameter`	Plate diameter	160 mm	100 to 300 mm, steps of 1
`thickness`	Plate thickness	4 mm	2 to 10 mm, steps of 0.5
`wheelDiameter`	Wheel diameter	66 mm	30 to 120 mm, steps of 1
`wheelWidth`	Wheel width	26 mm	8 to 50 mm, steps of 1
`wheelInset`	Wheel well from the edge	10 mm	4 to 40 mm, steps of 1
`motorHoleSpacing`	Motor bracket hole spacing	18 mm	8 to 50 mm, steps of 0.5
`motorHoleOffset`	Motor holes from the wheel well	10 mm	4 to 30 mm, steps of 0.5
`motorHoleDiameter`	Motor bracket hole diameter	3.4 mm	2 to 5.5 mm, steps of 0.1
`casterHoleSpacing`	Caster hole spacing	30 mm	10 to 60 mm, steps of 0.5
`casterOffset`	Caster holes from the front edge	16 mm	8 to 60 mm, steps of 0.5
`casterHoleDiameter`	Caster hole diameter	3.4 mm	2 to 5.5 mm, steps of 0.1
`batteryLength`	Battery opening length	60 mm	20 to 160 mm, steps of 1
`batteryWidth`	Battery opening width	34 mm	12 to 100 mm, steps of 1
`batteryBack`	Battery opening behind the centre	8 mm	1 to 60 mm, steps of 1

Notes

The plate is laid out from the wheels inwards. Wheel wells are 3 mm larger than the wheel all round; give the wheel width without the tyre bulge. If the wells would break through the edge, they move inwards on their own; the motor bracket holes sit inboard of each well, a pair front and back of the axle line, so an N20 or TT motor bracket bolts on with the motor shaft reaching into the well.

The ball caster holes are at the front (+X); the battery opening sits behind the centre and shrinks if it would run into the caster or the motor holes. Default holes are 3.4 mm, for M3 screws.

For laser cutting or a CNC router, open the Plate sketch and export it as DXF (acrylic and plywood in 3 to 6 mm work well); for 3D printing a 4 mm plate is stiff enough for a 1 kg robot. Add your own holes for the controller board by sketching on the top face.