A collimation article by NILS OLAF CARLSON (sorry NILS if I MISSPELLED} HAS A SECTION ON HOW TO BUILD YOUR OWN SIGHT TUBE , CHESHIRE EYEPIECE,ETC AND ALSO A GOOD COLLIMATION ARTICLE. SEARCH THE ARCHIVES AND YOU WILL RUN ACROSS IT.OR SOMEONE ELSE WILL CHIME IN WITH THE WEB PAGE.