The abutment structure is attached at {HEAD ~ the opposing sides} of {TAIL ~ the seaming board proximate} one of the opposing ends, and is adjustable between a closed condition opposing the upper surface and an open condition away from the upper surface and the opposing sides of the seaming board 
of
The abutment structure is attached at { HEAD ~ the opposing sides } of { TAIL ~ the seaming board proximate } one of the opposing ends , and is adjustable between a closed condition opposing the upper surface and an open condition away from the upper surface and the opposing sides of the seaming board
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH