Veritas MkII power sharpener update
Paul M. in San Diego
>A couple of weeks ago, I posted how much I liked this machine. The only drawback I found was I couldn't flatten the backs of wide chisels without rounding the edges. Today I figured out how to flatten backs with this unit.
I have a #7 jointer with a blade that was flattened on a waterstone with a slight dish in it. The end result is a blade where the back is ever so slightly thicker in the middle than the edges. The chip breaker has had problems seating flat on the blade and it frequently jammed with shavings. I've found that once a blade is "humped" this way due to a dished waterstone, that I can't seem to reflatten the blade by hand as the blade always rocks on the hump while moving it across the waterstone.
The secret to flattening blade backs on this unit is to never bring the blade to the spinning wheel. The slightest mistake in presentation angles causes the edges to be ground away very quickly. Instead, start up the motor with the blade already on the wheel, and shut off power before pulling the blade away.
I removed the tool rest to get it out of the way. I put on the finest 9um grit platter, and laid the blade on the wheel so that the business end of the blade is pointing away from the direction of rotation. I pushed down firmly on the blade with two fingers while holding the non-business end of the blade that hangs off the edge of the platter. I found that the startup jerk is not so bad as I turned on power with my other hand.
I got the feel of this at 9um, but realized that this blade needed too much work. I moved up to 20um and finally 40um to get this flat across the front edge before going back down the grits to 9um for finishing. The end result is much better than I've seen with the King 6000 waterstone (which is the finest one I have).
I then sharpened the bevel, which took only a minute or two. I took Lyn's message to heart, and used both sides of the platter equally, and had no problems with out-of-square edges. I also found that this naturally cambers the blade slightly, which is something I prefer.
