Originally Posted by
wallHax
I have an old steel frame without cable guides on the bottom of the BB. Would it be safe to drill a hole and mount one of those plasticy cable guides?
A lot of vintage bikes were intended to use a clamp-on guide like these (the Zeus and Campy ones):
https://bikerecyclery.com/cable-guides-stops-clips/
which would be a nice period touch if your chainstay cable stop is on top.
They fell out of favour when indexed gears became the norm, replaced by the under-bracket plastic guides.