The Achilles tendon is the thickest tendon in the body and is built for dynamic/explosive movement. So when you get on a standing calf raise machine and bounce up and down, the Achilles has no problem performing that work, sparing the calves of most of the tension involved. In order to shift that work to the calves, you need to remove as much of the stretch reflex as possible and focus on maximally lengthening and shortening the muscles.

• Hold the stretch position (bottom) of a calf raise for 5 seconds on every rep.
• Then hold the contracted position (top) for 3 seconds on every rep.
• Lower slowly and repeat.

Try 4 sets of 12 reps, rotating through different calf exercises each time you work them. Do this at least twice a week. If you've been a bouncing all this time, then be prepared to actually feel your calves working for the first time ever. Also be prepared for a tremendous amount of soreness. The extended time in the stretch position will also help take care of a tight Achilles.