@gsagostinho Here's a screenshot of the problem I was having. After moving the osc2 phase and returning it to zero, the waves weren't lining up. As @rjp9 suggested, I needed to reset osc1 to zero also.

@rjp9 Thanks for taking a look. That was certainly the problem - ha, I even said it in the title - the oscillators weren't in sync. I added phase reset to the first oscillator when i bang the oscillator slider.

I want to be able to look at some simple waveforms and see how they change as they go out of phase. I've set up this patch. The waves stay in sync for a few minutes, but slowly become slightly out of sync. The waveC Canvas shows the result of the two waves. If the waves are 0 offset, it should just be a larger sawtooth. However, the wave has a change halfway down the tooth.
phaseexample.pd