Make the value of the ending keyframe of your first animation match the value of the starting keyframe for your second animation, then set the interpolation for the curve between the keyframes to Constant (or Linear should work as well) by right-clicking the curve in the Keyframe editor.
--
Mark Spencer
Freelance Producer/Editor/Motion Graphics Artist
Apple-certified Master Trainer
Author, Motion 4 from Peachpit Press
http://www.applemotion.net