Scratches on my Shiro blade

[Mike]

Got a new PP – 3 sharpened a few knifes all came out super sharp. I then reprofiled my Shiro Neon down to 14.5 degrees per side and went thru the stone progression knife is sharp with even bevels but I got a bunch of nasty scratches on the blade. Should I have taped the blade up or how can this be avoided?

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Gazillion, sksharp

[Mikedoh]

I would think taping the blade would help. Also being careful when wiping the blade and making sure the stones are flat against the blade and not rotated when moving them on/off of the blade during sharpening.

When I’m concerned with cosmetics, I tape the blade. I will also tape over pivot areas in general to keep debris out.

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Gazillion, Mike

[Marc H]

Mike I’d want to figure out how and why you got them.  Not just cover the knife side to prevent them.  The scratches are mostly perpendicular to the knife edge.  Towards the tip the scratches almost traverse the entire knife’s side.  I can even see some at the spine side.  They also are into the crisp shoulder implying to me the scratches came late in the sharpening progression.  You can’t lay protective tape that close to the bevel to prevent those.  Your scratches are not a fine light scratch you get in random directions  across the blade from wiping the metal dust.  Something you did was dragging the abrasive culprit straight across the knife’s side while you did an up-down motion.   It’s odd the scratches are almost entirely in this this direction!

Mike were you wearing protective gloves that maybe had metal grit stuck on the finger tips that was getting dragged across the knife’s side.  I’d want to know how it happened and prevent it. You need to figure out the cause, not apply a shield to the knife.

 

Marc
(MarcH's Rack-Its)

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Gazillion, Mike, sksharp, Alan, David

[tcmeyer]

It looks to me that the stones were allowed to stroke beyond their length, thus dragging the tip of the stone past the shoulder of the bevel.  Other than correcting your stroke technique, I’d suggest putting a down-limit on your rods to prevent strokes from dropping below the bevel.  Some fellows have used a nylon clamp-collar on the rods, thereby limiting the length of the down-strokes.  I have back rubber (or neoprene) washers which fit tightly on the rods.

When I first got into using glass platens with diamond film I had some similar scratches, as the top corners of the glass were not deburred well enough and left some nasty scratches on the side of the blades.  For a while, I taped the entire exposed side of the blade, right up to the bevel shoulder, but then I eventually refined my stroke length.  I start and stop my stroke within about a half inch of the ends of the stones and I polished the corners of my glass platens.

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Gazillion, Mike, sksharp, Alan, Organic, Marc H

[Mikedoh]

I think Tom’s nailed it.

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Mike

[Mike]

No not wearing gloves.

[Mike]

Tom, Yes the stones did drop down quite a bit probably a big part of it I will look at the glass platen’s as well.

Thanks for the help,

[sksharp]

Hello Mike,

I had the same issue when I started. I used nylon collars and washers under the stones(put on the rod below the stone) to prevent the stone from getting below the the apex.

After awhile I took a few of the nylon collars, spacers or bushings depending on what you want to call them, and tapped nylon screws into the side so I could tighten them in place on the rod to use as stops for the stones.

I don’t use them anymore. After using them a while I got used to the movements plus slowed down. I don’t like to use stops on the rods anymore because they restrict my movement (which was exactly why I started using them, but became a hindrance after a while) and don’t have a problem with scratching the blade anymore, but I’m always aware of it. You don’t have to re-finish to many of those by hand to remember not to scratch the blade in the first place. I think that most of us have experienced exactly what you have here, but it’s something that most of us deal with in out own way. I’m sorry you have to experience it but, as they say, that’s part of the learning experience unfortunately.

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Gazillion, Mike, Marc H, Organic, wickededge

[Marc H]

Mike, each of us have our preferred method.  I use extra long rods because my vice is mounted a little higher on a riser block.  So I always, (except with strops) use both upper and lower stops to limit my throw or stones travel.  I have once too many times gone off the steel over the top of the bevel and returned down with a bang on the apex.  It can cause quite a ding.  Also I don’t want to slide down below the knife an get scratches similar to you had.

The most recent “stop” I started using are like these nylon lock collars, for 1/4″ ID.  They’re available from several mail-order suppliers.  If they’re too snug you can ream them a little larger with a rat tail file or a drill.  I like these because they’re easily adjust and lock tightly in place and have a small diameter that doesn’t seem to hold the stone off to one side when I’m setting rod angles.

Marc
(MarcH's Rack-Its)

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Gazillion, Organic, wickededge, sksharp, Mike

[Mike]

Those collars look like they will do the trick as a learning aid until I get more proficient with the movement of the stones.

Thanks for all the help.   This is a great forum with lots of helpful info.

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sksharp, Marc H

[Author]

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