25 mm square aluminium tube drill guide

use this guide for drilling 5mm hole to join two 25 mm aluminium square tubes at 90 degree with 25mm x 3mm aluminium flat bar and 4.8 mm pop rivets. the drill passage can be replaced with fresh ones for precise drilling. drill holes before cutting off the 3mm thick flat bar for better alignment. the last file is for the original one piece guide with guiding hole that can not be replaced.
the first pair of guides is for joining a tube with lip with a no-lip tube, the second pair is for joining 2