  We report a detailed three-step roadmap for the fabrication and
characterization of bulk Cr tips for spin-polarized scanning tunneling
microscopy. Our strategy uniquely circumvents the need for ultra-high vacuum
preparation of clean surfaces or films. First, we demonstrate the role of
$ex$-$situ$ electrochemical etch parameters on Cr tip apex geometry, using
scanning electron micrographs of over 70 etched tips. Second, we describe the
suitability of the $in$-$situ$ cleaved surface of the layered antiferromagnet
La$_{1.4}$Sr$_{1.6}$Mn$_2$O$_7$ to evaluate the spin characteristics of the Cr
tip, replacing the UHV-prepared test samples that have been used in prior
studies. Third, we outline a statistical algorithm that can effectively
delineate closely-spaced or irregular cleaved step edges, to maximize the
accuracy of step height and spin-polarization measurements.
