cheap tools should last for the 1 mod they was intended to work on,
each time they do something new, they get a new kit with a new bit anyways,
or buy a few of the tools as needed. it's not like there $10+ a piece for the bits.
make deferent things like
a over clocking kit (for deferent systems), with tri wing or game bit, printed instructions, and parts needed.
pre made vacuum formed cases,
make a few costom heat sinks from time to time, not all things need to be mass produced.
just something like a cut down GC heat sink with the in-lade fan. will not need more then a few of them around, but would turn a good profit.