4 convolute screwing taps size 1 1/2" 6 t.p.i. for cutting screw threads in four progressive stages. Convolute screwing taps circa 1840
4 convolute screwing taps size t.p.i. for cutting screw threads in four progressive stages. Convolute screwing taps circa 1840
8 convolute screwing taps by Johann Georg Bodmer, c 1840. 8 convolute screwing taps by Johann Georg Bodmer circa 1840