Original sentence: After peening, the edge is finished and subsequently maintained by very frequent honing with a whetstone or rubber (fine-grained for grass, coarser for cereal crops), and peened again as necessary to recover the fineness of the edge
Edited sentence: After peening, the edge is finished and subsequently maintained by very frequent stropping or  honing with a whetstone or rubber (fine-grained for grass, coarser for cereal crops), and peened again as necessary to recover the fineness of the edge