Blade Alignment (True Vertical)
- This topic has 8 replies, 5 voices, and was last updated 05/02/2017 at 12:03 am by
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Rich, You are exactly correct in your observation. This is the clamping tilt or cant caused when clamping a Full Flat Ground (FFG) blades in the old style clamp. As you determined, one side of the clamp is fixed, the other side moves out as you tighten the screw. There are various posts in this Forum on correcting this error caused by clamping. In essence you split the summation of the total error between the sides and correct each arm angle individually to correct for it. So 1 arm you add to the desired bevel angle and one arm you subtract from the desired bevel angle. You can attempt to use a shim of sorts to make a physical correction for the clamping error. This is hard to do repeatedly and predictably.
This clamping error was the impetus for WE designing the Gen 3 Self Centering Clamp. Which is what I wrote about in your other thread where I asked you which model WE you used. There are also some YouTube videos on this subject, “Correcting for Clamping Error on Wicked Edge”. On a good note, I found, the clamping error is consistently the same each time you clamp the same knife in the same position. So I recorded this error in my sharpening log for future reference to set up the knife for future sharpening. The error will still be there whether or not the spine is clamped parallel to the WE.
Marc
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I believe the cant will happen with any blade, FFG or otherwise. I wish I would have known before my recent purchase, I would have given much consideration to the Gen 3!
Rich,
You might try adding more tape/foam to the insides of the jaws. With large tapers to the blade, you need a little more foam. I get the best results from Moleskin. Another trick is to adjust the space of the jaws, top and bottom so they’re parallel, to the thickness of the spine. Then lightly snug the top and then tighten the bottom. With enough tape/foam/moleskin in place, you should be able to get the jaws vertical. It sounds complicated to do, but once you’re used to it, it’s actually pretty easy.
-Clay
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Rich: I went another direction and decided to take the angles into account with a fixed setting. I laid the left face of the blade against the vertical face of the left jaw, then cranked the lower screw to rotate the right jaw until it laid flat against the right side of the blade. If you’ve measured the angular displacement between the two faces of the blade, you can adjust for it with your angle. For example, my Delica 4 has about 3.5 degrees between its two faces. Knowing that the left face is held vertical, we know that the blade is leaning 1.75 degrees to the left, so I deduct 1.75 degrees from the left rod and add 1.75 to the right. It may be more than you want to deal with, but it works.
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