Albert Barnes Commentary 1 Samuel 13:20-21

"but all the Israelites went down to the Philistines, to sharpen every man his share, and his coulter, and his axe, and his mattock; yet they had a file for the mattocks, and for the coulters, and for the forks, and for the axes, and to set the goads." — 1 Samuel 13:20-21 (ASV)

The best rendering of the passage is perhaps as follows: But all the Israelites went down to the Philistines to sharpen whenever there was bluntness of edge to their shares, coulters, prong-forks, and axes, and to point their goads (1 Samuel 13:21). Coulters and mattocks were cutting instruments of the same type as the plowshare.