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My Sharpening Rig: Inspired by WickedEdge and ApexPro [Pict Heavy]

Discussion in 'Maintenance, Tinkering & Embellishment' started by Lagrangian, Aug 12, 2011.

  1. Lagrangian


    Jun 25, 2011
    As virtuovice would say, "Hi Knife People!"

    I'm fairly new to being a knife enthusiast; I only started about two months ago, so I'm fairly newbie-ish and my collection only has five knives. I got started with being curious about sharpening and advanced steels.

    I very much like the ideas behind the WickedEdge sharpening system, as well as the EdgePro, but I can't afford several hundred dollars for a sharpener, so I had fun building one myself.

    The sharpener has two orientations, "WickedEdge Mode" and "EdgePro Mode".

    Here is the sharpener in "Wicked Edge Mode":

    Here is the sharpener in "EdgePro Mode":
    Notice that the rig is basically rotated by about 90 degrees. In this mode, the knife clamp is used to hold a platform, and then the knife can rest on that platform, similar to the EdgePro setup. Right now, this is just a concept test; I still have to build some stuff to make this mode actually work.

    One disadvantage of the WickedEdge geometry is that it is difficult to sharpen a knife to less that 15 degrees per side (30 deg inclusive). This is because the knife clamp gets in the way. The EdgePro setup has no clamp, so there is no limitation on how small the sharpening angle can go. I wanted this to experiment with sharpening with extremely small included angles.

    For normal sharpening, I like having the knife completely clamped and fixed, and I like the idea of rapidly alternating strokes on each side of the blade, which is why I usually prefer the WickedEdge setup.

    By using a 4-inch bench vise, I can change the orientation of the rig, and get which-ever setup I want. At around 10 to 15 lbs, the bench vice is heavy enough to use without mounting/bolting it to a table. The vise is useful for lots of stuff besides sharpening (drilling, sawing, filing, etc.).

    More details and photos below, if you are interested. At the end I'll include list of specialized parts and a basic "blue-print" for the setup. Comments and suggestions are welcome; please let me know what you think.

    The main mechanical part is a spherical ball joint, which guides the rods. I wanted a fairly rigid setup, so I'm using 1/4" precision ground steel shafts. Here is a sequences of photos for the spherical joint.


    Here is the spherical joint itself. The guide rod slides through the joint and can pivot. The joint is an RBC Heim HM4, which is a "precision spherical joint."

    I wanted to protect the spherical joint from ingesting swarf and abrasive particles, so I have shielded it with a sleeve bearing, and a bit of plastic film.

    The spherical joint is mounted in a carrier which is clamped to the two side rails using two bolts. Here's the back view of the carrier.

    The central pillar is a knife-clamp from a sharpening kit (you can buy the clamp by itself). The knife-clamp has been filed down for sharpening 15 degrees per side. It's mounted on some 1"x1/4" steel bar. The white material in the center is epoxy putty.

    The hones are Moldmaster stones from CongressTools.com (recommended by Ankerson). For now, I'm just crudely rubber-banding them to the shafts with a spacer to prevent scratching of the shafts. I'm thinking about how to make a better attachment system for stones, as well as a more ergonomic handle. If you have any ideas, please let me know. I also made some leather strops which I can mount on the shafts (not shown).

    It seems possible to sharpen scissors with this setup, by using a right angle bend in the platform. This is just a concept; I haven't actually built all the parts to try this.

    Not really a blueprint, but here's a layout of the design:

    If you're interested in making a similar rig, you can get most of the parts from McMaster.com
    Spherical Bearings: $12.22 (each) http://www.mcmaster.com/#catalog/117/1175/=dl0d1r
    1/4"Precision Shaft:$ 7.27 (each) http://www.mcmaster.com/#catalog/117/1058/=dl0dk0
    Sleeve Bearings: $ 0.81 (each) http://www.mcmaster.com/#sleeve-bearings/=dl0fk4
    1"x1/4"x12" Metal bar: $ 7.36 (each) http://www.mcmaster.com/#catalog/117/3634/=dl14ls
    1"x1/4"x6" stones: $ 4.00 (each, approx) http://www.congresstools.com/congresstools/catalog?action=getcat&parent=27
    4" Bench Vise: $66.30 http://www.mcmaster.com/#bench-vises/=dl0gbe

    You should browse through the entire McMaster.com catalog; I did not necessarily choose the best parts. For example, if I had to do it over, I would use 5/16" shafts/joints for additional rigidity, and I would look for stainless steel parts instead of non-stainless.

    Most of the assembly I did by using super-glue and super-glue-accelerator to tack the parts together instantly. Then for strength and toughness, I used epoxy and epoxy-putty.

    I'll post some additional photos/results once I actually sharpen my Endura 4. On a test knife (not shown), I got hair-whittling sharpness after using the 600 grit Moldmaster stones.

    Please let me know what you think; suggestions and comments would be great.

    Last edited: Aug 12, 2011
  2. eccvets

    eccvets Banned BANNED

    Sep 8, 2008
    holy hell, sweet man. I was considering building something like this one day but never really gave much though to it after I got good at using my paper wheels. two huge thumbs up for getting creative without going broke!

    P.S. great pics, great write up, and great design. Didn't realize the limitations of the wicked edge system of not being able to get those low angles.
  3. singularity35


    Mar 1, 2010
    Very nice build dude!
  4. Skimo


    Mar 28, 2009
    :thumbup: sweet man!
  5. razor-edge-knives

    razor-edge-knives KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Apr 3, 2011
    Dude, you're seriously a genius! I could never figure that out even with your blue prints! Great job bro!
  6. Komitadjie


    May 31, 2011
    Hey, that's nicely done! As a thought for a further modification, have you considered adding a threaded end to the rod, and a stone holder system like the EP? If you kept it the same size, you could use all the stock and aftermarket EP stones out there as well.
  7. singularity35


    Mar 1, 2010
    Yeah, he is. :D
  8. Cosmo7809


    Dec 4, 2008
    Very nice man! You do some great work.
  9. flraptor07


    Aug 2, 2011
    I'm with Komitadjie, I'd set it up to use the Edge Pro stones they're easy to get and they have a big selection. Great job I can't wait to see the finished working set up!
  10. TechExec


    Jun 27, 2011
    Excellent engineering. Looks great!
  11. Lagrangian


    Jun 25, 2011
    Thanks for all the "thumbs up!" guys!

    I'm unsure if I should double-post; I have a similar thread running on knifeforums.com. At knifeforums.com, I added some thoughts about my rig. You can find the thread here:

    The specific postes I added are:

    If you guys want, I can also post the same thoughts here too, at bladeforums.com. Just let me know.
  12. Call_to_Arms


    Apr 13, 2011
    I thought about this same thing, I couldn't figure out the mechanism for controlling the angle of the stones, i like yours, it doesn't have pre-measured stops but once its dialed in you would be all set.
  13. changeofseasons


    Jul 15, 2009
  14. dipbait


    Feb 9, 2008
    Dang man, I thought I was smart by rubberbanding diamond stones to ceramic rods.


    Then stropping with dowel rods loaded with green chromium.

  15. Lagrangian


    Jun 25, 2011
  16. Lagrangian


    Jun 25, 2011
    I thought more about that link you posted (thanks!). For a setup with a non-sliding rod, and with a sliding hone, beltman's setup has superior geometry/mechanics. (beltman's rig: http://www.bladeforums.com/forums/showthread.php/809918-New-and-improved-Wicked-Edge)

    Here's what I mean:

    In my setup, the reachable-volume is a cone. This isn't ideal, because it doesn't fit the knife well. A gun-turret joint (like in WickedEdge or EdgePro) fits the knife better, because it's reachable-volume is pyramid shaped. Similarly, beltman's setup fits the knife well too. For beltman, his spherical joint setup can reach a huge area, similar to a large cylinder with two cones removed. Kind of hard to explain, so here is a diagram with partial perspective. Hope this makes sense.

    On the left is my setup. The middle is a "gun-turret" joint. On the right is beltman's setup.

    In addition, beltman's setup is more mechanically robust; the main force along the axis of the rods is considered to be a "radial load" for which the spherical bearing can support huge forces. An "axial load" would be in the direction that tends to push the sphere out of the outer racing, and for that the joint is less strong (but probably more than strong enough). So the more I think about it, the more I think beltman's setup is superior!
    Last edited: Aug 13, 2011
  17. changeofseasons


    Jul 15, 2009
    Makes sense. The big picture is mostly on a 2D plane though. With a spherical bearing you are limited to a set side-to-side distance. With the other two setups, the size of blade you can sharpen is only limited by the length of your rod. :) Does this matter? Not unless you're sharpening an extremely large blade.

    Since WEPS paddles fit 1/4" rods, that option will work with your setup. But that won't allow you to use whatever stone you want unless Clay will sell blank paddles. Currently there is no quick way to adjust for differences in stone thickness with the WEPS. You can use the stop collar trick with the EP, but the thickness of the paddles prevents the same thing being done on the WEPS. My best idea to overcome this is to make a custom paddle for the WEPS that quickly secures and releases EP style stones. Something like that might be useful for your design. But it will be a week or so before I have a working model to test.
  18. Txknifefan


    Jul 9, 2011
    Very nice design, looks like it will last a long time.
  19. Nosmo


    Jul 12, 2003
    For those members that want to experiment, IGUS in Germany make spherical rod ends in 1/4 inch with plastic/teflon balls. These are precision but also alow a SS rod to slide easily without chatter. I have used this setup ( for ten years ) and the ball end shows no wear. Igus USA will send you free samples if asked.

    Last edited: Jul 17, 2017 at 3:17 PM
  20. Lagrangian


    Jun 25, 2011
    Wow, that is one beautiful sharpening rig; so cleanly designed! :D

    btw, I think you can buy those polymer IGUS spherical joints/rod-ends from McMaster.com, Amazon.com, as well as elsewhere; they're surprisingly inexpensive. I have a few of the Igus spherical joints, but I bought the wrong ones; I got the ones which were slightly loose because they are supposed to be compression fit into a hole. After compression fitting, the extra "play" is squeezed out of them, but I didn't know this. So, if you get some, be sure to check the specifications from the manufacturer's website (not just the reseller's website). I think the rod-end ones are probably more precise out-of-the-box, and don't need to be compression-fit (like in your rig).
    Last edited: Aug 13, 2011

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