Help – scratches on blade

[Mark Massie]

Hello everyone,  I am a long time user and this year I have upgraded to the Gen 3 vice with the original pro pack diamond stones that are at least 6-7 years old.  I am not an expert but not a novice either and have successfully sharpened hundreds of knives.  However, since I started using the Gen 3 vice, I am see scratches on the blade below the bevel on both sides of the blade and simply cannot figure how this is happening as I am using the same set-up technique that I have always used. 

I have attached two pictures of the both sides of a blade I sharpened as well as a picture of the set up used to sharpen the blade.  When establishing the angle, for this blade, I simply selected the lowest angle that would prevent the stone from touching the clamp.  I know the picture is not great, but the stone is absolutely only touching the bevel of the blade and is not touching any part of the blade below the bevel.  I am literally ruining the blades and cannot understand how this is happening.  Any help or ideas would be much appreciated.

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[tcmeyer]

Those are scratches caused by letting the stones slide off the bevels.  It may be related to your upgrade to the Gen 3 vise.  Is it maybe a little higher than before?

[Mark Massie]

Sir,

Thanks for your reply.  When I set the knife up, the stone was only touching the bevel.  I did use an up and down scrubbing motion, but the stones never left the bevel that I can recall.  I am not sure how the stones left the bevel, but I will take another look.  I have gifted the old vice so I no longer have it to compare the height of each vice.  I just know that my set-up and sharpening technique has not changed from one vice to another so I am very stumped.  Thanks again for your reply!

[NotSharpEnuff]

Mark,

When I upgraded to the newer vise I added plastic stop collars for the stones.  When I set my stones I move the stone to the extreme edges of the blade.  At the farthest point with the stone about a ~1/4″ above the bevel I set the stop collar.

From what I can see from your pics, the knife was set with the handle very close to the vise.  With most of the blade at the far end the stones may be sliding below the bevel at the end of the stroke.

Ed K.

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tcmeyer, Marc H

[tcmeyer]

Mark:  As we used to say when I was in the “black shoe navy”,  you needn’t call me “Sir.”  My parents were married.

It seems like we all get these scratches eventually.  Usually, you never notice it when it happens.  Later on, you’ll see the scratches and wonder how they got there.   The more serious sharpeners, most notably those who do it for paying customers, develop the protocol of taping up every exposed bit of the knife, handle and all, just for these situations.

As NoSharpEnuf say, installing some form of clamp collar will prevent most of them.  The trick is to be religious about setting them with the start of each job.  Unfortunately, they won’t prevent the same thing from happening on an edge that reaches beyond the limit of the clamp setting.  In these cases, you’ll want to cover the entire face of both side of the blade with tape, leaving only enough untaped to expose the very edge for sharpening.  Maybe even double up on the tape if you’ll be using one of the coarser grits, which cut thru tape more easily.

For us hobbyists, we’ll eventually develop a reliable stroke technique which minimizes the chances of a slip.  I always use the one-side-at-a-time method, so I can closely watch the stone’s face relative to the edge.  For this I lean my head to one side or the other and get very close to the blade, so I can be more confident in my strokes.  On Thursday, my nephew came over to learn a few lessons for his PP 2 system.  Not having used it more than a few times, his strokes were pretty shaky.  It made me cringe, knowing that I too once had the same degree of unfamiliarity.  It just plain takes a while to develop the hand/eye skills.

 

[Mark Massie]

NotSharpEnuff and TCMeyer,

Thank you both for taking the time to reply to my posts.  I really appreciate your valuable insight and willingness to share your thoughts.  What was so confusing to me is that I never had this problem with the previous clamp.  After remounting the knife in the same manner and position as originally used and looking at everything, I believe that this clamp is taller than the old one and I need to adjust my muscle memory because this had to happen on an upward sweeping stroke where the top of the stone it the blade instead of just the bevel.   Thanks again Gentlemen.

Mark

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Marc H

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