Isikulufu sethu esisethiwe senziwe ngensimbi ye-alloy enamandla amakhulu, eyenziwe ngokunemba ngomshini futhi iphathwe ngokushisa ukuze kuqinisekiswe ukuqina nokuthembeka okuhle kakhulu. Inhloko ye-Allen yakhelwe ukuthi ifakwe kalula futhi isuswe, futhi ingasebenza kalula ngesikrufu sika-Allen.
Akukhona nje ukuthi isikulufu esisethiwe asiqedi isidingo sokubhoboza ngaphambili noma ukuthunga ngesikhathi sokufakwa, kodwa singalungiswa kalula ku-shaft ngokusebenzisa inani elifanele lokucindezela ekusetshenzisweni kwangempela, ukuqinisekisa uxhumano oluqinile futhi oluzinzile.