  Spin squeezing provides crucial quantum resource for quantum metrology and
quantum information science. Here we propose that one axis-twisted (OAT) spin
squeezing can be generated from free evolution under a general coupled-spin
model with collective spin-spin interactions. We further propose pulse schemes
to recover squeezing from parameter imperfections, and reach the extreme
squeezing with Heisenberg-limited measurement precision scaling as $1/N$ for
$N$ particles. This work provides a feasible method for generating extreme spin
squeezing.
