Electric Snow Blower,Electric Leaf Blower,Battery Snow Blower,Electric Leaf Blower Cordless Ningbo Hoya Electronic Commerce Co., LTD , https://www.jauhitools.com ZM40 plunger pump cylinder (Fig. 1) processed by our factory, the material is QAl9-4, the main technical requirements: (?) 19mm hole roundness tolerance 0.005mm in the depth of 52mm, surface roughness R_α0.2, seven holes (?) The perpendicularity of 19 mm to the end face B is 0.03 mm. Under the condition that the matching clearance between the plunger and the plunger hole is 0.02 to 0.03 mm, seven holes are required to be interchanged.