Pair of old straddle milling cutters, 5" diameter, hole at centre 1" square

These hand-made milling cutters were probably made for use on a mandrel in a lathe. The work mounted on the cross slide would be passed between them. The teeth are not radial but 'behind centre', and therefore give a shearing action.

The only way in which cutters could be sharpened at the time these were made, was by softening, filing, and re-hardening.