Specimen of segmental planing in cast iron

The two bronze specimens of helical planing, with pitches of 11 and 37 inches respectively, were prepared on an ordinary planing machine, with the work held in a headstock, which made a partial revolution during the travel of the table. They were acquired from Manchester engineer Richard Roberts in 1860. The other specimen is a reed moulding cut in cast iron, to a circular arc. It was done on an ordinary planing machine, on the table of which was placed a second table, or sector, centred on a stud attached to the stationary bed. The sector was attached by two chains to eyes secured to the table, which by its motion caused the sector to swing horizontally; the work was secured to the sector at a distance from the stud corresponding with the radius required.