Grinding on a wheel provides a particular challenge in that you have to hold a consistent position or else the angle of your grind changes. Various jigs exist for 10" wet grinders but they're all designed for straight or upswept edges rather than forward-curving like scythe blades--even the mighty Tormek lists scythe blades under items that they tell you to grind freehand. But creating a good hollow is critical to mowing with ease, so I whipped up this little jig for my Grizzly G1036 to make the task easier. Bent steel round stock with the ends flattened and drilled and acetal bushing stock used for the rollers. The stone turns in the direction of the tool rest (which I clamp a dressing tool to for truing the wheel and otherwise don't use) so it pulls the blade into the rollers, keeping the blade in the same spot on the wheel and allowing me to more easily hold a consistent angle as a result.
A
video of the grinding jig in action:
Not the same blade (I only ground a section of one side for demonstration--you
should grind the full length equally on both sides in case your blade is laminated) but here's a video of what a freshly hollow-ground blade is capable of. That's a 20"+ deep swath out of a 30" blade!
While it takes a while to regrind the bevels on most vintage blades, it only needs to be done once in a VERY long time as long as you don't smash your edge into a hidden wire or fencepost. The increase in cutting performance makes it well worth the approximate hour or so it takes to refresh the bevel on a beat up antique blade.