Lewis said there was progress on the two most vexing issues - using student test scores to evaluate teachers and giving more authority to local principals to hire teachers.
The union is concerned that more than a quarter of its membership could be fired because the teachers work in poor neighborhoods where students perform badly on standardized tests, which Emanuel wants to use to evaluate teachers.
"This is really not a 'gotcha' evaluation system," Byrd-Bennett said. "It's to make sure we have a very high standard ... that will keep the very best teachers in front of our students every day."
Lewis said the union fears Emanuel plans to close scores of schools, putting unionized teachers out of work. In recent years about 100 public schools have been closed, with officials usually citing low enrollments. At the same time, a similar number of publicly funded, non-union charter schools have opened.
Both sides agree Chicago schools need fixing. Chicago students consistently perform poorly on standardized math and reading tests. About 60 percent of high school students graduate, compared with 75 percent nationwide and more than 90 percent in some affluent Chicago suburban schools.
The fight does not appear to center on wages, with the school district offering an average 16 percent rise over four years and some benefit improvements. Chicago schools already have a projected $665 million budget gap for the year that began in July, a key factor driving Emanuel's reforms.
More than 80 percent of Chicago public school students qualify for free school lunches because they come from low-income households.
"Teachers feel beaten down throughout the country," said Randi Weingarten, national president of the union including the Chicago teachers. "They feel beaten down because of austerity, because of test- rather than teacher-driven policies, because of a spike in poverty, because of the demand on them to do more with less - and then blame them when that doesn't work out."
"That's what's created all the frustration that you hear on the picket line," she said.