Over the years we have found diamond stones to be invaluable. they get the job done quickly and they remain flat. DMT stones hone the final edge on every Barr tool.
Single grit, Diamond Whetstones® are available in fine 600 grit, coarse 325 grit, and extra coarse 220 grit.
Duo-Sharp®, 2 sided are available in extra fine/fine, fine/coarse and coarse/extra coarse.