For quad shield RG6 coaxial cable use the reducer that you use for RG8x / RG59.

Use a UNIBIT no. 1 to drill into the reducer so that the hole is 5/16 inch.

I marked the bit so that I won't drill that mark which is larger than 5/16 inch.

Use a 5/16 -18 to tap no more than 2.5 turns. You can skip this.

Remove no less than 1 and 3/8 inches of the pvc jacket.

Carefully twist the reducer, not the cable, into place.

Final assembly is TOP SECRET.

Please consider the first time you do this as a pilot. Reducers vary in quality.