MacCullum, your description of how the cylinder reel is aligned in the sharpening machine is not detailed enough to indicate whether the result will be good or bad. It would be a bad idea if the mower frame is being used as the blade alignment jig, because the key relationship is between the reel and the bedknife, not the reel and the frame. The traditional solution is to make the reel true to its axle after sharpening, rather than true to the mower frame. Sharpening the reel true to the frame could result in the reel being tapered along its length, which might work in the short term, but could cost you a lot of blade material if the next time you sharpen it, you go back to a traditional method and grind off a whole lot more of the blades to bring it back to parallel. In addition to this there is Deejay's point: if the reel is sharpened while mounted on loose or worn bearings, you will end up with a lot of irreplaceable blade material ground off but a reel that is worse than it was before sharpening.
