That clinches.
1567. Turberv., Poems, To his Love (R.). With clinching clawes … and talents sharplie set.
1725. Pope, Odyss., XV. 180. A milk white fowl his clinching talons bore.
1873. Dixon, Two Queens, II. X. i. 155. Isabel meant it as a clinching bribe.
Hence Clinching-iron = CLINCHER 3.
1874. in Knight, Dict. Mech., I. 567.
