Full definition
A precision-machined split tapered steel sleeve that clamps a pulley, sprocket, or coupling hub concentrically onto a shaft by driving the tapered bushing into the matching tapered bore of the hub using cap screws. The taper (typically 1:16, or 8° included) converts screw axial force into enormous radial clamping force, eliminating the need for a separate key in many cases (though a keyway is standard for torque backup). European standard series: 1008, 1108, 1210, 1310, 1610, 2012, 2517, 3020, 3030, 3535, 4040, 4545, 5050 — number indicates bore range and bushing OD. Bore sizes: 10-125 mm. Installation torque values are critical — overtightening can crack the hub. Removal: transfer screws to jacking holes. Brands: Fenner, Martin, TB Woods, Dodge. Per BS 3790. Interchangeable across all major manufacturers.