1, check whether the blank size meets the maximum size requirement of the drawing shape;

2. File the datum plane of the outer contour according to the drawing requirements, and meet the requirements of (60±0.05)mm, (80±0.05)mm, verticality and parallelism.

3. Draw the processing lines of all concave-convex bodies according to the requirements of the drawings, and drill 4-3 mm process holes.

4, processing convex parts:

(1) Saw off the vertical angle according to the scribing, and rough file and fine file the two vertical surfaces. According to the actual size of 80mm, by controlling the size error value of 60mm, we should control 80mm minus (&; Shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; ) mm range, so as to ensure that meet the size requirements of () mm; Similarly, according to the actual size at 60mm, by controlling the size error value of 40mm, it should be controlled within the range of 1/2×60mm actual size plus () mm, so as to ensure the size (&; Shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; ) mm, while ensuring its symmetry within 0.1mm.

(2) Saw off another vertical angle according to the scribing, and control and file the size (&; Shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; & shy; ) mm, as for the size requirement of convex surface () mm, it can be measured directly.

5. Machining concave parts:

(1) Drill a row of holes with a drill bit, saw off the excess part of the concave surface, and file it roughly until it is close to the line.

(2) According to the actual size of 80mm, the concave top surface of the fine file is controlled with the size error value of 60mm (here, the size is controlled as two vertical surfaces of the convex end surface) to ensure the matching accuracy with the convex end surface.

(3) For the vertical plane on both sides of the fine file, according to the actual size of 60mm contour and 20mm convex surface, one side can be subtracted from the size of 1/2×60mm & by controlling the size error value of 20mm, for example, the size of convex surface is 19.95mm; Shy; & shy; & shy; & shy; & shy; () mm, and the other side must control the size of 1/2×60mm minus &; Shy; & shy; & shy; & shy; & shy; () mm, in order to ensure that it can meet the requirements of matching accuracy with 20mm convex surface, and at the same time, it can also ensure its symmetry accuracy within 0.01mm.

6. Chamfer all sharp edges and check the accuracy of all dimensions.

7, sawing, requirements to reach the size of (20+/-0.5) mm, saw surface flatness of 0.5mm, leave 3mm without sawing, and finally trim the burr.