GB1311586A - Rough finishing and honing bores in workpieces - Google Patents

Abstract

1311586 Honing SOC ANON AUTOMOBILES CITROEN 5 July 1971 [7 July 1970] 31370/71 Heading B3D A lapping tool comprises a plurality of first and second radially displaceable thrust members 6, 7 protruding from a hollow body 1, the first thrust members having radially inner faces inclined to the centre line of the body at a lesser angle than the inner faces of the second thrust members, an expander 10 having two sets of surfaces, one set inclined at the angle of the inner faces of the first thrust members and the other set at the angle of the inner faces of the second thrust members, and an expandable split sleeve 13 surrounding the thrust members had having first portions 18 coated with relatively coarse abrasive lying radially outwards of the first thrust members and second portions 19 of relatively fine abrasive lying radially outwards of the second thrust members. The body 1 is connected by a universal joint 2 to a drive spindle 4 and is formed with longitudinal slots 5 for receiving the thrust members 6, 7 which alternate around the body. The expander is in the form of a mandrel 10 axially movable within the body 1 by a rod 12 and is formed with grooves 8, 9 receiving the inner surfaces of the thrust members 6, 7, grooves 8 being inclined at the same angle as the inner surfaces of the members 6, and grooves 9 being inclined at the larger angle of the inner surfaces of the thrust members 7. The expandable sleeve 13 is split at 14 and located on the thrust members by projections 15 on one 7a of the thrust members 7 engaging openings 16 in the sleeve. The surface of the sleeve is divided by longitudinal grooves 17 into alternate segments 18, 19 forming the first and second portions, the first portions 18 lying outside the thrust members 6 and being coated with abrasive, such as a diamond charged compound, and the second portions lying outside the thrust members 7 and being coated with a similar, but finer, abrasive, both portions being formed with serrations. Apertures 20 in the grooves are provided for a flushing fluid. At the start of a honing operation, the thrust members 6 project more than the thrust members 7 so that the coarser portions 18 of the sleeve effect honing. As the mandrel 10 is moved in the direction F the thrust members 7 are moved radially outwardly faster than the thrust members 6 until the finer portions 19 project more than the portion 18 to effect a fine honing.