Jose,
Congrats on your new possession. Sorry I haven't posted photos. My camera is over 1,000 miles away! I'll be gone for the summer. Maybe next year. Check out photos linked to other posts. I think you only begin to understand the HobbiGoni after you've used it on many knives, and especially at various stages of sharpening, or re-sharpening the same knife. It would be instructive to take a knife that's been damaged or purposely dulled, then examine with the HobbiGoni at each stage of re-sharpening. Maybe next year when I have my HobbiGoni and camera and knives in the same place I'll do! I don't understand "measure each side independently". The instrument shows both sides, one on each side of the scale so you can examine, compare each side.
Tom

When you receive the HobbiGoni termed a "Laser Knife-Edge Protractor" you find an enclosed booklet of User Instructions. It shows diagrams and patterns of reflections from thin and thick knives, curved or hollow ground surfaces. The key item mentioned is that "the closer the reflection is to a full and bright dot the nearer the surface is to a perfect mirror polish."

In my experience, I found that I needed to use the instrument on various knives, looking at various patterns to educate myself on what I was seeing and why. If I saw a bright dot on each side of the scale, I knew that I had achieved a flat, highly polished surface on each edge. If I found that I had more than one point, or an angled line, or a blurred, wide reflection, I knew that I had something less than perfection. Over time, comparing the reflections from the laser with what I was able to observe about the knife edge under a microscope, I've educated myself regarding what imperfections of sharpening technique correlate with what patterns of reflections in the HobbyGoni.

One of the surprising things I discovered was that a couple of Masamoto knives I had newly acquired from Japan, one an HC, the other a VG, had rather blurred, indistinct reflections when viewed with the HobbyGoni. My initial reaction was that the HobbyGoni was a rather crude, not very useful instrument. Over time, re-sharpening, polishing these knives, I achieved much more precise reflections with the HobbyGoni confirmed by real-world improvements in cutting performance.

www.catra.org.uk/product_p/cuhg.htm

Sorry for the misspelling in the heading. Couldn't find a way to edit after posting!

Tom

I'm wondering if it might be useful to have a separate thread on the HobbyGoni? I know it appears a couple of times under other topics, but suggest it might be useful enough to deserve a topic of its own? I've owned mine for a couple of months now and only lately discovered what a valuable asset it is. For those who are not familiar with this device, it is a laser product for determining the existing angles on a knife, available from England, running about $150 including all the taxes and shipping to this country.

While in theory it only reveals angles on each side of the blade to within 2 degrees, I find with mine I can easily determine the angle accurate to 1 degree. More important, it reveals the quality of the edge. If the edge is perfectly ground, perfectly flat, the angle shows as a very tiny circle on the scale. If there's any kind of burr remaining, or secondary angle, or rounding of the edge, the point of light shows as more than one point, or as an elongated blur of light on the scale. Sometimes, I've had difficulty telling if there is still a slight burr by feel; the HobbyGoni clearly shows if there is a burr remaining.

While $150 is not a trivial expense, I've spent far more than this on various stones and strops which I haven't gotten the full benefit from, as I have not been able to tell if my technique is good enough to get the edge I had hoped for. I've found that even under a microscope, I've been able to tell how polished my edge is, but not how precise in terms of coming to a point, creating a flat grind, eliminating burrs, or achieving the angle I desire. The HobbyGoni is better for these issues, and also more accurate than a marker, as well as much quicker, for determining angle. The problem with using a marker for determining angle is it involves destructive testing. The HobbyGoni gives an answer much quicker and without altering the edge.

The other aspect of this instrument that is important to note, is that on first use, with new knives direct from the manufacturer, the Hobbigoni appears to give very crude, not useful measurements. This turns out to be the fault of initial grind, not the Hobbigoni. The Hobbigoni is simply revealing what is there. If the initial grind is crude, the pattern shown by the instrument looks crude as well.

So much for my rant as a new convert. I thought might be useful for others.

There's almost too much information, too much testing, too many photographs! I'm overwhelmed! Think I'll get the leather strops and try the smallest pastes. It has so much to do with direction of movement, number of passes, technique! I'll know more when I've gone back to the strops and try on my own. Thanks for the help, references, there's really no lack of information on the forum! This really goes way beyond practicality. My knives are really sharp enough. But as a hobby, much fun and less expense than restoring classic cars or old homes...

What about after the micro-fine?

Okay, maybe I'll order a pair of leather strops again and give a try. Which strops and paste would you recommend once I finish with the micro-fine ceramics?

Good suggestion where I find leather strops too difficult. Expensive, but maybe less hassle in the long run!

I understand using leather strops on short knives using just up motion. On a 240mm Gyuto not so easy. Maybe I'll look into using finer stones. Or just being satisfied to end with ceramics!

I really like the Murray Carter video as it demonstrates difference before and after stropping. Can someone clarify for me what "stropping" might mean? I go as far as the extra fine and ultra fine ceramics. What is the next, "stropping" step? Could I get a barber's strop and use that? What are my options? I tried the leather strops from WE but could never master. Always ended up slicing the strops to ribbons before I got very far with my knives!

sub 20* inclusive angle?! Didn't know such a thing exists! Where? I've sharpened my Gyutos to 12* degrees on each side for a 24* angle and even this I find hard to maintain without chipping!

Yeah, the video of the Konosuke HD Gyuto is the kind of thing I'm talking about. I have a couple of Japanese Gyutos that I've polished with the WE ultra fine ceramics and come close to this, but not quite. The idea of polishing on newspaper is something I've not tried! Gives me something to aspire to. On the other hand, finding some truly ripe, juicy tomatoes might do the trick!

Semi serious question. For years I've tested the sharpness of knives on how easily they slice paper. SOP. But sometimes I see youtube examples of slicing through tomatoes with no apparent effort. In general, no matter how sharp I get a knife, no matter how finely polished the edge, it seems that I have to saw back-and-forth a couple of times to get slice started on a tomato. Am I lacking something in my sharpening technique or am I living in an area where tomatoes have thicker, tougher skins? Are tomatoes graded according to how thick, tough their skins are? How do I know if it's the fault of my sharpening technique or the tomato?!

Let me be sure what is being asked here. First, once the angle cube is laid flat on the base and zero'd I find that it will consistently read zero when re-placed in the same location. Now, when the cube is laid against either arm, then moved and replaced, readings can be expected to vary slightly. This is because the position of the cube on the arm can vary, the position of the arm on the knife edge can vary,and finally the pressure of the cube against the arm can vary. There is a slight give, or bending of the knife itself in response to pressure. In summary, a variance of a few tenths of a degree is nothing to be concerned about.

One item not mentioned, which should be, is that the manner in which the vise clamps secure a blade vary depending upon how they are tightened. The WEPS needs an upgrade so it is possible to rotate a knife blade to achieve 90 degrees relative to the base every time. Otherwise, it is all too easy to have a degree or two of variance every time it is clamped into place. It doesn't do much good to use a sharpee or angle cube to set the angle for the stones if it is not possible to control the angle of the knife itself.

Doing much research on the internet, this is one of the most muddled topics I've seen! Many conflicting, contradictory explanations regarding the value of asymmetrical edges as well as the proper means of sharpening. The discussion so far seems good in that as indicated, asymmetry can be achieved either by having the same angle on each side, but the edge displaced one way or another, or the same displacement with different angles on each side. The best rationale I've seen is that with a very thin blade, having most of the sharpening on one side you can achieve a very thin, fine-cutting edge without losing so much metal on the other side that it is easily chipped.

The idea of a knife inherently being asymmetrical doesn't seem to me to make much sense as you can order the same knife sharpened for either left or right-handed use.

I'd like to hear from people who have used a right-handed knife left-handed or right-handed or the reverse and know if they've actually experienced any difference in how it cuts.

While we're on the subject, I thought I'd clarify the need for the Angle Cube given that the WE sharpener already has a scale for angle adjustments. The scale is only approximate and needs to be compensated for depending on the width of the knife being sharpened and the thickness of stones. For example, with my chef's knives which are about 2" wide, the angles need compensation for the fact that the edge is higher above the clamp than on a narrower knife. Also, Chosera stones are thicker than the WE diamond stones. That changes the angle as well. So, My Shun chef's knives have a factory edge of 16 degrees. Using the WE stones, I have to set the WE angle settings to 18 degrees to get 15.6 degrees as measured by the Angle Cube. When I switch to the Chosera stones, I have to move the WE settings to 20 degrees, again, to get 15.60 degrees.

A couple of quick reactions. I thought that the Angle Cube has a zero set button so that you can place it against what you are using as vertical (or horizontal) and set it to 0, then against the stone being used on the WE to get a relative angle?

Second thought, it occurs to me that you could use the WE as a make shift laser goniometer. Place your knife in the holder, as you would to sharpen a knife, then suspend a cheap, laser pointer above the knife edge facing down, then see and mark where the "bubble" laser images hit on each side of the base. Once marked, take a straight edge with the Angle Cube and determine the angle. It doesn't matter how high above the knife edge you suspend the laser, as (since it is collimated, going straight down) it will be deflected the same number of degrees to each side, based on where it hits the edge and the edge angle, independent of how high above the edge your laser pointer is. Clear?

I'm going to Home Depot or Ace today and see if I can find a stand to suspend the laser pointer above the edge, so I can try, take a photo and clarify what I have in mind. But it may be a simple, doable way of creating a home-made goniometer that gets past the 1.7" blade width limitation of the one from CATRA.

Thanks for response. I just ordered an Angle Cube, but don't see how I can use on just the final edge as actually sharpened. Can the Angle Cube sit on such a narrow edge? If it can, that would be great as that is what I wish to measure!

Question about the CATRA Laser Goniometer. It gives specs of measuring knives up to 1.7". I have chef's knives with 2" wide blades. Is there any way of using the goniometer to measure such blades, i.e. some sort of work-a-round?