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Convex bevel width; primary bevel scratching

Recent Forums Main Forum Techniques and Sharpening Strategies Convex bevel width; primary bevel scratching

This topic contains 24 replies, has 5 voices, and was last updated by  tcmeyer 11/07/2018 at 12:03 am.

Viewing 10 posts - 16 through 25 (of 25 total)
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  • #47997

    tcmeyer
    Participant
    • Topics: 32
    • Replies: 1636

    Just to re-affirm what Marc points out… even with the improved fit between handles and guide rods, there is still a significant change in angle between pressure applied below the edge and pressure applied above it.  The stone will “rock” about the edge as a lever on its fulcrum.  It can be close to one full degree on my rigs.  If I see that I’m not erasing the scratches from the previous grit near the apex, I usually can simply move my hand up on the handle to correct the error.  Even my bushing-equipped handles, which have nearly zero slop will show an angle change of several tenths.

    Angle change and Organic’s comment about preserving your fingertips has been part of my sermon for a number of years now.  Fingers below the edge – good.  Fingers above the edge – bad.  Try placing your thumb in the second groove from the bottom.  That should place you index and middle fingers in the second and bottom grooves.  Then stick with it, for consistency.  And when setting your angle with an AngleCube, try to apply the same amount of pressure at the same point on the handles

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    #48003

    Drew
    Participant
    • Topics: 10
    • Replies: 42

    I just checked, and with knife contacting center of stone, there’s .3° change between top and bottom pressure… Just spent 10 minutes staring at the WE, going “…huh.”

     

    I sure as sin’ll be holding from the bottom now, but it complicates using the cube on the 1.5k stone. I’ve always taken readings from top closest corner. I didn’t find any difference between cube reading top or bottom of stone, but is there some hidden danger at reading angles at the bottom?

     

    Tips are going to be more challenging. I see the safety benefits of grip bottom. The only real bad cut I’ve gotten is scrubbing the tip, sliding off, then pulling back. Tip carved a good miniature version of a fillet mignon steak out. But, gripping bottom feels a lot less stable. Stone wants to roll on the blade off parallel. Just slow it down for tips?

     

    Feels like I just leveled up in a video game, and all the same monsters just got harder. Good trade for consistency, though.

     

    That’s a good idea, using the “slop” as extra reach when needed.

     

    Off to go redo all the knives in the house. No wonder my convexing was getting scratched. You all are career-savers.

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    #48004

    MarcH
    Moderator
    • Topics: 53
    • Replies: 1373

    Drew, remember the angle setting of your bevel is “relative” to that knife individual knife clamped in that orientation and that specific position in the vice jaws.  It is a relative angle not a true or real angle.  All that matters to match that angle again is consistency.  It truly doesn’t matter where or how you place the magnetic digital cube on the stone as long as you do it the same way consistently, each and every time you set the angle on that same knife.  You may find that on some knives it’s easier to place the digital cube at the bottom of the stone.  As long as you do it for each knife, again, the same way consistently, it’ll give you repeatable relative angle settings.  I try to do everything the same way all the time for simplicity of the consistency.  If I have to change up my technique or method, I note this in my sharpening log, where i can record specific comments on sharpening  each particular knife.

    In reality a bevel you sharpened to 15º per side with your Wicked Edge may be different from my 15º bevel on my Wicked Edge. It may measure with a Catra device at a true 14º or a true 15.5º.  It really doesn’t matter.  If the bevel angle we applied using our individual Wicked Edge Systems, that we measured to be 15º is sharp and it cuts and works well for us, this is all that matters.  If it measures at something other than 15º with a true measuring device it doesn’t make the edge any less sharp or a bad angle.  Too much emphasis is placed in the angle number when we knife sharpen.  Like it gives bragging rights or make the knife better.  All that matters is the knife’s performance.  And that is very personally subjective also!

    You may want to look into these safety tools.

     

    Marc
    (MarcH's Rack-It)

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    #48021

    Drew
    Participant
    • Topics: 10
    • Replies: 42

    Ok, I did a few days of convexing, holding the stones at the bottom, and taking readings from the bottom of the stones. I’ve got to tell you, I will never hold the stones up high again as a default technique again. I can feel the shape of the edge so much more finely, and my bevels have never been so crisp.

    I highly suggest telling newbies about the angle changes with top and bottom grips. I only remember reading about the safety aspect. This is like discovering second gear after driving for months in first.

    Thank you all. I’m seeing the results that I can finally be happy with.

     

    PS, Marc: I bought a pair of cut proof gloves on Amazon. Good suggestion. Also, I could get addicted to precision measuring equipment. I’m going to hold off looking into things like the Catra until I get established. But since we’re on the topic, what dual axis protractor would you suggest? Something that registers adjustments quicker than the angle cube.

    Pps, tc: I tried the .5° stepdown. The knives I had to work with were freakishly soft steeled CuisineArts. Even the 1.5k stones were too aggressive, and I kept wiping my bevels out… You, my friend, have got to have a surgical hand. I’ll try it again when I refresh these edges in a few weeks, but you may simply be a specialist at a difficult technique. Hat tip.

    Ppps, Organic: I’ve been meaning to tell you, your blog guided me to my first successful convex. Screwed the first two attempts up, then just power read your articles for a couple hours. Hella thorough work, man.

    #48022

    MarcH
    Moderator
    • Topics: 53
    • Replies: 1373

    Drew I use the Floureon Digital Protractor DXL360S, as does tcmeyer, I believe.  It has the specs claiming it is the most precise gauge, with the lowest resolution.  I cannot say or claim it is as fast or as easy to use as other devices I have used also, those with very good results, too.  I used the Wixey WR300 Type 2 for a long time with good consistent results.  I found the Wixey to be the fastest locking and easiest to use gauge of all of them, I’ve tried.  On paper it does not have the precision or resolution of the DXL360S, while it never inhibited good, consistent results.

    I think that “consistent technique” and “attention to detail” are the largest contributors to your results, more so then using the precision measuring equipment.  I’ll submit to you that your improved results with the new hand hold positions is more a result of you gaining a little more experience each time you sharpen and slowing down and paying closer attention to the details then simply the new finger and gauge placement, you employed.  I generally place my gauge at the top of the stone and my fingers centered on the stone and I can match a bevel “dead on” with the first stroke that I applied a year ago when I do a edge refreshing touch-up.  Each time you sharpen you’ll continue to get more aware and get more in tune with every aspect of what your doing as your stones continue to break in and allow for better improved results.  You’ll find you’ll use more of your senses and the sound of the stones becomes a good tell of how well you’re bevels are getting.

     

     

    Marc
    (MarcH's Rack-It)

    #48023

    Organic
    Participant
    • Topics: 16
    • Replies: 642

    Ppps, Organic: I’ve been meaning to tell you, your blog guided me to my first successful convex. Screwed the first two attempts up, then just power read your articles for a couple hours. Hella thorough work, man.

    I’m glad that you’re getting improved results, but I don’t know what articles you are making reference to. I have never written a blog post about convex sharpening. Perhaps you have me confused with another member? I know Tom (tcmeyer) has written about convex sharpening on the forum in the past.

    #48024

    Drew
    Participant
    • Topics: 10
    • Replies: 42

    Marc: I imagine more experience has a lot to do with it. I’m just grateful to have eliminated that .3° rock in the paddles. I swear the scope shows cleaner bevel edges. I keep cringing when I think that I’d been putting the equivalent of a .3 microbevel on just parts of the blade…

    Here in a few months, I’ll look into one of those cubes. The stock one doesn’t register fine adjustments as quickly as I’d like, and getting “15.5 to 15, nope, shoot, 14.5, ok, 15….. crud, 15.5 again” is a little maddening. Real time, no lag readings would be a nice upgrade. And thousands of a degree real-time, ideally.

    Organic: apologies. I finally tracked it down. Molecule Polishing was done by Mark76. For some reason, I associated it with you.

    https://moleculepolishing.wordpress.com

    If you haven’t already explored it, it’ll hook you in for several hours.

    My appreciation of you is still valid. You’ve given loads of hints over the last several months.

    #48025

    Organic
    Participant
    • Topics: 16
    • Replies: 642

    I’m glad to be of service.

    Yes, the molecule polishing blog was written by Mark76 and is a great read. He was a moderator on this forum for many years and was a very helpful fellow.

    #48032

    tcmeyer
    Participant
    • Topics: 32
    • Replies: 1636

    For the benefit of the newbies on this forum, Mark76 was Mark de Weger, who lived in the Netherlands.  Mark was a good friend and mentor to many of us here.  We lost him last Christmas Eve at the age of 50, far too early for a good soul.

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    #48033

    tcmeyer
    Participant
    • Topics: 32
    • Replies: 1636

    Pps, tc: I tried the .5° stepdown. The knives I had to work with were freakishly soft steeled CuisineArts. Even the 1.5k stones were too aggressive, and I kept wiping my bevels out… You, my friend, have got to have a surgical hand. I’ll try it again when I refresh these edges in a few weeks, but you may simply be a specialist at a difficult technique. Hat tip.

    Not likely to be a highly develop level of skill.  The amount of material to remove with each step is highly dependent on the thickness of the edge at the bevel shoulders.  The thinner the blade, the fewer and lighter your convexing strokes should be.  Try very light strokes and start out with very few strokes.  Change the direction of the strokes to make it easier to see the transition point.  Watch the new bevel and how closely it approaches the apex.  Stop when you see the new bevel reaching about one half to two thirds of the way up the main bevel.  Then take the number of strokes (and how much pressure) it took to get there as an indicator of what to do with all successive steps.

    Because the first step will be initially hitting the shoulder of the bevel, its facet will seem to grow in width very rapidly, hence my use of only 3 or 4 strokes at each step, beginning immediately after you’ve stoned the main bevel at the apex.

    I use “half-degree increments” because I follow the detents in the Gen 3 Pro.  I don’t use my angle cube at all during the convexing process.. I rely on the detents to give me repeatable step angles.  It doesn’t matter if it 0.4 or 0.7 degrees per step.  You could probably get the same, or very similar results by making half as many adjustments, stepping one degree at a time, but with more strokes per step.  If you’re using a standard rig (not a Gen 3 Pro or commercial rig) you can use the 1-degree detents in the angle bar.  Just remember where the detent was for the main bevel.

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