Gear pump housing requires two holes for high precision machining. In the medium and small batch production, the general use of general-purpose machine tools and special tooling to processing, this processing method is difficult to achieve accuracy requirements. Gear pump from the processing methods, tools, fixtures continue to improve, a better solution to this problem, the processing quality is stable and reliable. After repeated testing, improvement. Is the use of the following processing methods: the two holes on the processing of both ends, 4-φ9 holes after the processing steps, and 4-φ9 a diagonal hole accuracy to φ9H8, for positioning. Then three holes are machined with R18.41 and φ12.5. The first process: In the lathe with rotary chuck car indexing R18.41 hole to R18.31 +0.065 + 0.035 (R18.41 with casting bottom hole), drill φ12.5 hole to φ11.5, and then boring to φ12 .4 ± 0.01. The second process: the design of special composite reamers, lathe (due to drilling spindle rotation accuracy is low, can not use drilling) at the same time reaming R18.41 and φ12.5 coaxial hole. Big hole hinge to R18.41 + 0.055 + 0.025, two small holes hinge to φ12.5S7 size. Gear pump housing requires two holes for high precision machining. The tool is mounted on the spindle (remove the chuck) and the tail end of the tool is provided with guide bearings on the clamp. Fixture mounted on the carriage (remove the knife holder), with a straight line indexing fixture. The third process: Drilling machine with a floating reamer to one of the small holes hinge φ12.5F7 size requirements. Fixture program and structure: Select the pump body G surface and two φ9 diagonal holes for the positioning of the fixture with two pins on one side positioning. Gear pump using linear indexing form. Clamp the part with two hook clamps. Clamp body 1 is an angle iron, with screws, tapered pins mounted on the carriage. Moving indexing block 2 and clamp body 1 through the dovetail guide rail, and with the bolt 3 lock. The indexing block 2 is provided with a cylindrical pin 4 and a chamfered pin 9 by which the part is positioned on the indexing block 2 and is pressed by the two hook- Seat 6 is used to support the rear end of the tool. With hand-drawn cylindrical indexing on the agency. For the convenience of operation, the workpiece is installed on the right side of the fixture, and the fixture body is provided with holes on the indexing block for the tool to enter the workpiece processing. In order to prevent the chips from entering the joining surfaces of the members 1 and 2, a chip holder is fitted in the hole of the clip body 1. Gear pump housing requires two holes for high precision machining. Deutz Engine,Deutz Engine Parts Co., Ltd. , http://www.nsenginepart.com