Two things about doing my Old Hickories on my 1 x30 Delta is I hold the blades as close to vertical as possible, probably around 15 degrees. Using too much angle and too much pressure on these types of machines will wear away a blade pretty quickly. That, and I only use some old wore out 600 grit blades that have no real grit left on them..it's more a honing thing with the softer steels, than actually sharpening. Even on my newly made knives I never use more than 400 grit, since I grind to a pretty thin edge. The only exceptions are cleavers and machetes where I start with 220 and then 400.