Now I've made progress on the Loyd Carrier gearbox it inspired me to design a lightweight bevel gearbox for the Matilda, so here it is:
First a drive shaft is removed from a plastic short shaft gearbox, and nylon bevel gears acquired
Then the frames are designed and printed

The two frames are assembled with the shaft

Insert bearing into drive shaft mounting

Add a 5mm shaft, spacers and second bevel gear, the second gear will need a grub screw fitting

Then we have a gearbox

Located in the chassis

Fit the drive sprocket
And as they say in Yorkshire, Jobs a good un
Still some work to do on the gearbox to add a second bearing on the drive shaft, put some mounting holes in the base, and wait for the delivery of a 12v 200rpm geared motor and coupling from Amazon, and then I can progress.
Alwyn
