Congratulation on the purchase of your burn out oven controller. You
casting life will be a bunch easier.
I drilled a hole for my controller thermocouple in the back of my
oven about 2/3 up from the base. The coils are exposed and not
embedded in the insulation. If you coils are not visible it will next
to impossible to drill a hole as there is no way to know where the
The hole being in the back keeps the wiring out of the way.
It will be easier to drill from the inside to the outside. If you
prefer to drill from the outside to the inside be sure you don't run
into a coil.