Regarding wear of the parts. The top of the worm tooth on mine was very
sharp on the remaining non loaded side so the loaded side may have been
the same so slowly chewing through the wheel. When I replaced them I
radiused the edges on the worm carefully so hopefully this should
prevent too much wear in the future. The originals did do quite a bit of
work over a period of about 6 years or so.

My neighbour has one of these saws also, not Clarke though. The casting
are slightly different in some small details and the unit appears higher
quality due to the motor being decent UK motor rather than the chinese
cast iron TEFC, and other details such as knobs rather than hex bolts
etc. He has had it for maybe 15 years and done quite a bit of work but
when we removed the cover on the gearbox they look almost perfect. The
worm tooth on that one was radiused at the top.

J.S. Reed wrote:

My Clarke brand 4 1/2" bandsaw just gave up the ghost. The driven gear in
the gearbox is smooth as a baby's backside in several spots, and the teeth
are sharp as knives in others. Does anyone know where to get spare parts?
Does anyone know why this failed?
I would love to make a new gear, but I haven't tried it yet, don't have the
time, and understand that a worm drive makes the details very critical.