This is what I did on my 4*60 for the throttle cable: After marking the cut off location, I clamped the cable in a vise (not too tight- didn't want to misalign the strands). Then I used a cut off wheel on my Dremmel tool and cut through VERY slowly. The cutoff point was very close to the vise. The cut was very clean and didn't fray the end at all. The cable slipped into the tubing quite easily.

I DID, however, have a problem with the cable binding slightly when I operated the servo. The cable would "belly out" and not go into the tubing about 1/3 of the time. So I removed the nylon link from the carb end of the cable and pulled the entire assembly out (tubing and all since it was't hot glued very well). After removing the cable and tubing, I lubricated the cable and the inside of the tubing with a bit of Graphite powder and worked the cable back and forth. It really glided freely! I reinstalled the whole thing from inside the fuselage.

One more thing that was making the cable "belly out" was the hole size in the servo arm. It was a little too small and was causing the solder link and servo arm to bind slightly. I enlarged it to .067" from the .063 it was before. Everything works fine now. It seems to me that the tubing should be a bit longer on both the carb and throttle servo ends. Hope that helps.