Even before I've had a full set of parts for the prototype and I'm already making improvements…

Almost as soon as I'd frozen the design for the M0.1 Atomic Duck, I realised that it needed a slight adjustment to the front axle mounts to make the mounting more secure. In the M0.1 Atomic Duck parts, the stub axle (A002P005R001) screws into the steering upright (A002P002R001), there's no positive distance location to this connection other than the limit of the thread on the axle.

To improve this connection, I wanted to include a “stop” to the connection, so the revised axle (A002P005R002) can be screwed in tight to the revised upright (A002P002R002). This will give a bolted connection that can take a clamping load, and that will give a better connection for the threadlocking adhesive, which stops connection vibrating loose in use. This is especially important, as the thread direction is identical left to right, so one side could potentially suffer loosening through progression in normal use.

To do this, I've switched from an M20 (fine) thread on a 20mm diameter axle to an M18 (fine) thread on an 18mm diameter shoulder cut into the end of the 20mm axle. This means now that the shoulder face of the axle will mate against the upright.

Here are the technical drawings in pdf:

I've got a couple more modifications to go before I'll get to a position for another release however, better to think of this as an update to the development branch.