The center sickle overlap arrangement of a sickle type mower for a cutter bar that include a pair of sickles for reciprocating motion where each sickle is essentially half the length of the cutter bar for reduced forces and vibrations for high speed cutting. In the center, the sickle blades overlap at only guard and the blade of one sickle is inverted and co-operates with a top ledger surface of the associated guard so that both the blades are in proper shearing arrangement with the respective guard ledgers. Further the top ledger surface is adjustable to allow clearance adjustment to ensure tight clearance between all sickle cutting surfaces and guard ledgers. Further the arrangement ensures that all crop is cut between sickle sections and guard ledgers rather than between a pair of sections on the opposing sickles.