Flat "V" grinds and fixture-based sharpening systems?

[Naphtali]

I'm having difficulty sharpening my CS Master Hunter that has a flat grind. I use a Gatco fixture-based diamond sharpening system - similar to Lansky, but much wider stones. The difficulty is not the actual act of sharpening. Orienting the "V" configuration of the blade makes it difficult for me to clamp blade for even, regular sharpening on each side. Excepting freehand sharpening with my 8x2 inch stones, something I cannot use effectively, fixture-based sharpening systems of which I have knowledge all have this difficulty.

So what is my procedure to use my (Gatco, Lansky, et al.) fixture-based sharpening system successfully on flat grind blades?

 

[Haffner]

Some of the Wicked Edge clamps seem to have overcome this problem. I think they call them self centering clamps.

 

[115Italian]

Keep the front screw loose and tighten down the back screw. You may need to keep loosening the front screw as you go. You need to get a steep angle to grab the blade evenly.

 

[Obsessed with Edges]

Having used both Lansky and GATCO guided setups (and DMT Aligner as well), this is what universally worked for me, on FFG blades:

1. Loosen up both of the clamp screws enough that you can pinch the front end of the clamp fully flush to both sides of the blade.

2. While pinching the clamp flush to both sides, gradually tighten the FRONT screw until you just begin to feel resistance to it's turning. STOP turning the front screw there (and make sure the clamp is still fully flush to both sides).

3. Tighten the BACK screw until the clamp fully tightens flush to the blade. Check to see if the blade slips in the clamp, or to see if there are gaps showing any light between the clamp's jaws and each side of the blade. If it does slip, sometimes that's an issue with blade finish and or flatness of the (so-called) full-flat grind itself, which might actually have a tiny bit of concave/hollow or convex profile instead. Sometimes, taping the inside faces of the clamp can provide a little more 'grip' on slippery blades. The paper backing of wet/dry sandpaper also works well to grip the blade in such clamps, with the 'grit' side of the paper against the clamp itself.

The common assumption that one has to maintain the sides of the clamp parallel to one another is more troublesome than useful. Most blades won't be ground to fit that profile anyway, being tapered from spine-to-edge in many or most cases. Trying to keep the clamp sides parallel only means the clamp will never have a firm hold on the blade, which creates many, many more problems. I actually find FFG blades the easiest for these clamps, because they offer the broadest and flattest surface area for fully-flush clamping and therefore afford a very strong & stable hold on the blade.

It's more important to clamp fully flush to the blade, which keeps it from moving up/down or slipping in the clamp, and not worry as much about trying to keep the angle exactly the same on each side. This is because many (most) factory blades won't be ground perfectly symmetrical side-to-side (relative to centerline of the blade) anyway, and keeping the blade from moving in the clamp will prevent bigger issues overall, like edge rounding or inconsistent angle control (or complete lack of same).