A method for manufacturing a combination wrench includes pressing a wrench material piece in a sealed mold at a temperature without generating carbon scale to form a semifinished product including first and second driving ends and a handle interconnected between the first and second driving ends. The first and second driving ends of the wrench semifinished product are processed to form a combination wrench having a box end and an open end. The wrench material piece can be obtained by shearing a material plate
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