| 摘要 |
A method of forming a recess in a body (10; 24) having a cylindrical surface, and in particular a metering valve component, utilises a grinding wheel (32) having a first axis (33), preferably a drive axis, and a circumferential surface (34) concave to a second axis (37) that is substantially orthogonal to the first axis (33). The grinding wheel (32) also includes first and second opposing radial surfaces (36, 38) of substantially planar form. At least a portion of the circumferential surface (34) of the grinding wheel (32) is engaged with an outer surface of the body (10; 24) and the grinding wheel (32) is rotated about the drive axis (33) to cause a region of the body (10; 24) to be ground, thereby to define a recess (40; 46) in the body having a periphery (42; 48) at the cylindrical surface including at least two substantially square corners (41a, 41b, 41c, 41d; 49a, 49b) and at least one pair of substantially parallel facing edges (43a, 43b, 43c, 43d; 47a, 47b). The method is conveniently used to provide an opening or port of at least partially square or rectangular form in a cylindrical body such as a metering valve member (24) or a metering valve sleeve (10) of a metering valve arrangement. <IMAGE>
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