Any shop with a rod hone will also have a sunnen bore gage, accurately calibrated with a VERY precise "setter". If the OD mic is right on, a good hone operator can bring your dampner in within the specs you're asking for. Even there I would think the keyway should be filled to "almost" flush with the ID. Oh yeah, the honing oil has lanolin in it, and it gets into your skin to the degree that your sweat will smell like the oil.......Been there, done that!! Ray