These Shimano cable housing stops are designed to screw onto a frame mounted bolt. There is nothing stopping you from drilling a hole on both sides of the downtube and using a long through bolt, thru the downtube plus nut on one side. I would not do this, but depends on age and value of frame. I drilled out/made larger the cable stop holes at the top of the downtube on my new Spec. Chisel so as to run the e-tube cable for a Di2 shifter system.
https://www.amazon.com/SHIMANO-Housi...19707293&psc=1