Otherwise a wedge shaped metal corner bracket with {HEAD ~ an aperture} therein to pass {TAIL ~ a bolt} through is attached to each frame corner 
to pass
Otherwise a wedge shaped metal corner bracket with { HEAD ~ an aperture } therein to pass { TAIL ~ a bolt } through is attached to each frame corner
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH