Edge Pro

[Cliff Stamp]

...you have attempted to change the path on something when you're caught.

You are the one who quoted the review I wrote, I simply posted the rest of the paragraph to show how you were misquoting it.

Where, a few posts ago, you recommended not using the EP stone because it would wear out too fast, and change the angle, now you completely ignore that and post a section that it will take too long

No I didn't ignore it, the Edge Pro coarse stone wears fast, when I bought it Dale even recommended to buy an extra one. Fred has noted that he can wear one out in a single night. I would not in general recommend extensive regrinding on the coarse stone simply because you don't need high precision when you are shaping and a large x-coarse stone will both be faster and much cheaper.

When I wrote the review eight years ago I had not used a belt sander and had not extensively worked with micro-bevels. The amount of work I have done since with knives and sharpening obviously changed my perspective. I would now recommend a belt sander for adjusting the edges on knives and as I noted I don't use jigs any more. I don't use training wheels on a bike any more either, but it doesn't mean they don't work. Come on guy, that is a weak arguement even for you.

Interesting that you state all it does is "improve cosmetics"... considering an Edge Pro sharpening ranked top in 6 out of 8 categories in your "World's Greatest Sharpener" contest.

Yes, Ben sharpens knives very well.

Suggests that it does a little more than "improve cosmetics"

You would need to compare the results of Dale's freehanding and even then all you could say was that for him the Edge Pro produced a sharper blade. Lots of makers can produce very sharp edges without jigs, R. J. Martin, Dozier, and Spyderco.

... or will you be changing the results of that too...

Obviously as new results come in. The last dozen samples that I sent out people never returned which is kind of amusing as the blades cost about $0.25 so it is kind of retarded to actually go out of your way to steal two of them especially since they are heavily used. This is why that webpage hasn't been updated in awhile. I bought another pack about a month ago and sent them out.

[change]

... now that it no longer fits in with your current view on sharpening?

Yes, gather more information and it changes your perspective. It is called learning.

Let's see in the last couple of weeks, you've redefined the definition of a convex edge, stropping, and now an Edge Pro and Sharpmaker don't work. What's next?

Keep up to speed guy, last week I invented the internet, the portable computer, the "motor car", sliced bread, cured the common cold, made major advancements towards world peace and invented a completely healthy breast implant which requires no operation.

-Cliff

 

[cbwx34]

Cliff,

It wasn't a misquote, the rest of that part of the review dealt with time, and not stone wear or angle change, which is what was being addressed.

Your statement "Lots of makers can produce very sharp edges without jigs..." doesn't really mean much, since by your own criteria, you would need to compare how they sharpen with a jig, for it to mean anything.

And by that definition, even you're own perspective is tainted. Since you have gotten rid of your EP several years ago, how do you know you couldn't produce an even better edge with one, than what you are currently doing now freehand, especially if you continued using one during that time?

Sharpeners, such as Juranitch, don't consider angle control "training wheels", but a necssary part of obtaining a good edge.

At any rate, to get this somewhat back on track, your original statements about the wear rate and angle change were not correct... in the context of changing the Sebenza it should do fine, and the angle change from stone wear is less than a degree. (Surprised you brought that up anyway, since "angle consistency isn't required here".... right?)

I thought Al Gore invented the internet.

cbw

 

[db]

I would assume if someone is spending the $$$ for an EP system they are doing so because they care about the looksand sharpness of there knives and edges. Not useing the EP for angle control and to evenly regrind edges seems to me as a waste of $ and time. Nothing wrong with caring about the cosmetics.

Keep up to speed guy, last week I invented the internet, the portable computer, the "motor car", sliced bread, cured the common cold, made major advancements towards world peace and invented a completely healthy breast implant which requires no operation.

-Cliff

I thought Al Gore invented the internet.

cbw

Cbw Cliff offen tries to rewrite history to fit his needs.

 

[Django606]

Hmm, I didn't realize the thumbstud would be a problem. I definitely don't want to remove it, CRK says that it cannot be removed without messing it up pretty badly.

Does anyone know for sure that the thumbstud is a problem with the Edge Pro, and if so, a remedy?

 

[bbcmat]

Not a problem on a Sebenza - just roll the tip towards the stone guide pivot until the stone makes contact to the base of the blade (just passing to the outside of the stud), then sweep / blend that postion into the normal position once that 1/4" of blade has been cut down.

Tape the thumbstud up, because touching the side of it with the coarse stone will make a flat on it and/or the step it contacts. OUCH !!

Once your back up to the 12+ deg per side range for your microbevel, the stone clears the top of the stud, and it no longer is a problem. (Large seb)

MAT

 

[bbcmat]

Cliff - you really bring out the sharpening in people - look at all members with axes to grind !

Hey Yooooooooo!

MAT

 

[Cliff Stamp]

Your statement "Lots of makers can produce very sharp edges without jigs..." doesn't really mean much, since by your own criteria, you would need to compare how they sharpen with a jig, for it to mean anything.

I have discussed their use of jigs and they can produce edges as sharp as Dale does on the Edge Pro.

Since you have gotten rid of your EP several years ago, how do you know you couldn't produce an even better edge with one, than what you are currently doing now freehand, especially if you continued using one during that time?

Because angle control isn't the limiting factor in sharpness, I determined that a long time ago by measurement, which was again one of the reasons I sold the Edge Pro. It simply wasn't useful for me, this of course doesn't imply I think it is useless in general as you stated, and if I felt it was I would simply say it.

Sharpness for a given steel type mainly has to do with matching the abrasive to the steel and optomizing the pressure to minimize the deformation/fracture burrs. I thought for awhile that angle control was was significant in terms of effecting time but proper optomization of microbevels makes that insignificant as well in most cases.

At any rate, to get this somewhat back on track, your original statements about the wear rate and angle change were not correct...

Yes they were, you are just concluding based on presuppositions not actually founded in what I said. I specifically, as noted, which you ignored again, said edges(s) not edge, as I assumed the poster having success with this knife would so regrind others.

Yes the stone wears fast, even Dale notes this, which again you ignored. Yes wear on stones induces angle changes, and if you are using a jig to set the angle precisely it should be obvious this could have an effect which would not be noted freehand.

As I have clearifed again, other times in great detail, there are more reasons why it is of benefit to use a x-coarse benchstone for regrinding than a jig. Mainly cost and time. When I first used the Edge Pro I was impressed I could regrind an edge is 10-15 minutes, now I do it in 1-2 and on harder to grind steels.

This time could not be improved on an Edge Pro and in fact it would be very awkward to try to replicate how I hand regrind edges using the Edge Pro.

Surprised you brought that up anyway, since "angle consistency isn't required here".... right?

If you are shaping then you generally don't care about the precision. However if you do use a jig with tight angle controls then it can obviously make a difference. For example set an edge on the Edge Pro at 20 degrees with the coarse stone and then polish with a finer stone at 19 vs 21 and see how long it takes to remove the scratch pattern in each and that is just a 1 degree difference either way. You can of course compensate for this by keeping the coarse stone flat and adjust the angle accordingly.

I thought Al Gore invented the internet.

He stole the idea from me while we were playing poker. I was discussing how our lab group was using protocols to multi-pass transfer academic information, it was when we invented the LASER. Basically we were using a multi-band FTP which was live updated. I noted some people were starting to use it for recreation. It started basically when a couple of the researchers started dating.

Bill Gates did the same thing, I said to him one day that it the main thing people needed in an OS was just ease of install/operation not security/functionality and sketched out a task switching program which ran on a basic shell which gave a windows interface. I was a bit concerned about the limited memory allocation abilities but he said that would not be a hard problem to solve.

-Cliff

 

[flatgrinder]

It's okay, but a 1" x 30" belt grinder (from Harborfreight, etc.) works well too. It's faster and all you need are a 120 grit belt, a felt belt (Jantz supply carries them) and some white rouge. If you know what you're doing, this works very well and produces a fine convex edge.

 

[cbwx34]

Cliff...

Yup, you're right, I was answering the question based on the knife and reshaping he asked about. I won't disagree that there are better ways to do major regrinding, especially if you're doing it quite a bit. And I won't disagree that the 120 stone wears faster than the others... again I was just relating it to the original question.

Still don't think you answered the question of how you don't know that a controlled angle edge would be better... unless you applied what you're doing now and added the control. If I read you right you're saying that you determined that angle control wasn't significant so now you don't consider it. I'm asking, how do you know angle control won't improve it? If you've made any improvements in sharpening since you sold your EP, I don't know how you would know. Of, course, I guess you probably need to tell me how you're defining 'significant' in this statement. But I find it hard to believe that in an area where a lot of sharpening is done on medium measured in microns, having angle control won't provide a better edge over sharpening without one. (And no, I'm not saying a person can't get a knife sharp freehand).

If I'm shaping either freehand or with an EP, and precision doesn't matter, than your statement about how long it would take to remove the scratch pattern really doesn't make sense.... because removing the scratches would also apply to the freehand shaping. Why would I just want to remove scratches from the EP shaping? In fact, wouldn't it take longer to remove the scratches from the freehand shaping, which would be less accurate, than the EP shaping?

And no, I'm not asking these to argue with you as alluded to in another post.

I thought Bill Gates stole DOS from IBM, and the Windows idea from Apple.

cbw

 

[gunmike1]

Cliff...


If I'm shaping either freehand or with an EP, and precision doesn't matter, than your statement about how long it would take to remove the scratch pattern really doesn't make sense.... because removing the scratches would also apply to the freehand shaping. Why would I just want to remove scratches from the EP shaping? In fact, wouldn't it take longer to remove the scratches from the freehand shaping, which would be less accurate, than the EP shaping?

cbw

Because in the edge pro, if your coarser stone sharpens at a slightly more obtuse angle due to wear or whatever than your next grit stone, you will be reprofiling the work you did on your coarse stone with a finer grit (for instance you use the 20 degree setting, but the coarse stone sharpens at 21 degrees and the finer stone sharpens at 19 degrees). That means your fine stone is reprofiling from 21 to 19 degrees, not very efficient. Obviously, if the finer stone is working at a more obtuse angle than the coarse stone it will remove the scratches very quickly. I have never personally used the edge pro, and actually would like to get one, so I can't comment on the actual stone wear versus angle issue, but Cliff's conceptual point about the differing angles from stone wear in the same setting in the jig make perfect conceptual sense to me.

 

[cbwx34]

Thanks for the reply gunmike1, but that wasn't the point. The short question is, why is it an issue to sharpen out the scratch pattern soley using the EP. but not freehand to EP? In either case, you'd have to adjust accordingly.

cbw

 

[Cliff Stamp]

I'm asking, how do you know angle control won't improve it?

I have measured the sharpness using jig systems very recently, I switched mainly to freehand in the last few months after determing the angle variation in hand honing wasn't significantly effecting the results. I always assumed it would be a big issue because everyone says it does. It isn't. The main issue is burr removal which is more sensitive to pressure, edge condition, stone suitability, stroke pattern, etc. .

I guess you probably need to tell me how you're defining 'significant' in this statement.

The difference in two means is significantly greater than the confidence interval from the standard deviation of the difference in those two means, with the p value of <5% random variation. I sometimes use medians and calculate the same thing using a transformed IQD to estimate the standard deviation.

But I find it hard to believe that in an area where a lot of sharpening is done on medium measured in microns, having angle control won't provide a better edge over sharpening without one.

Because the sharpness of an edge is independent of the angle at which it is formed.

In fact, wouldn't it take longer to remove the scratches from the freehand shaping, which would be less accurate, than the EP shaping?

Since you know the hand reshaping is not well constrained you take this into account when determing the angle to apply. People don't do this with the Edge Pro which is why I noted it happens. You can of course compensate for it just like you would freehand by decreasing the rod angle to adjust for the increase due to stone wear. There would be then no difference there in speed of refinement as both are pretty much instant. For example if you hand grind at 10 with x-coarse DMT and then refine at 15 with 600 DMT it happens almost instantly meaning just a few passes.

It should be noted however that some people have strict tolerances for angles they use for example setting a chisel for the wood and steel type and how the wood is cut. But because knives are so multi-purpose this generally isn't a concern. Unless of course you carry a lot of them and really make them all very distinct in use. Even then though, you will have that ability over time. Johnston for example awhile back finally measured the angles he hand hones on his stockman, they range from about 5 for the cutting blades and 10 for the utility ones and are very consistent. Of course when you are starting out then jigs are much easier.

I thought Bill Gates stole DOS from IBM, and the Windows idea from Apple.

Everyone does, I constantly get gifts such as T-Shirts with "The man behind windows" from friends/family which is a joke which is only funny to them. It does however break the ice at bars.

.... but Cliff's conceptual point about the differing angles from stone wear in the same setting in the jig make perfect conceptual sense to me.

That's a dangerous path to follow.


-Cliff

 

[db]

I have measured the sharpness using jig systems very recently, I switched mainly to freehand in the last few months after determing the angle variation in hand honing wasn't significantly effecting the results. I always assumed it would be a big issue because everyone says it does.

Not everyone says that it does. In fact most hand sharpeners don't.Welcome to the dark side.

 

[Cliff Stamp]

When you are starting out then precise angle control is a big issue, experienced hand sharpeners will actually be extremely consistent and thus they are essentially using a jig, it is just a natural one. Once you switch to using proper multi-bevels the requirement for angle control is minimized anyway. For a long time I didn't like micro-bevels because I viewed them as reducing cutting ability because they are more obtuse that the primary bevel. However from a force responce point of view, a knife without a micro-bevel simply lacks the proper relief bevel. The nature of the relief depends on the exact use of the knife but it is always less than the apex angle. In the above however I was mainly speaking of the variation in angle from one trial to another that hand sharpening would produce, Landes work showed this isn't a significant variable. Buck's work also makes this point but isn't as obvious because there you can only see the noise in a run where Landes shows you the variation from one run to another.

-Cliff

 

[cbwx34]

Cliff,

Thanks for the reply... to be honest though it's pretty vague and with no real content.

Perhaps you could point me to some more specific posts you've made on some of this... (actual testing and results) either here or on your website.

I'm sure you wouldn't accept it if I said, "I've measured sharpness with jigs recently and found that it produced a much higher level of sharpness". Your reply I would bet would be... let's see the numbers.

The biggie I don't understand in this post is "the sharpness of an edge is independent of the angle at which it is formed."

Are you saying within the confines of sharpening freehand, or in general? Cause I read that and think... so I could sharpen a knife at any angle, and as long as I account for burr removal etc. the knife will be equally sharp? (Hope that made sense).

Thanks

cbw

 

[Cliff Stamp]

Perhaps you could point me to some more specific posts you've made on some of this... (actual testing and results) either here or on your website.

I have done many edge retention comparisons freehand in the last few months which have been posted. The initial sharpness isn't lower than obtained by jig sharpening on the sharpmaker, I would never have switched otherwise. As a minimum I accept edges that push cut newsprint at about an inch and I consider that a bit sloppy and optimal is 2-3". If you go back even a year or two then I was just looking for a clean shave with any push cutting ability.

The main reason I didn't freehand in the comparisons was of the angle variation. Landes however used precise ground blanks with edge stability measured by machine and still had ATS-34 fourth from the top (dozen+ steels) in one trial and fourth from the bottom in another due to the inherent difference in the steel in the same blade. This explained the variation observed no matter how tightly I constrained the work. This meant that freehand doesn't induce a significant uncertainty due to angle variance because the steel itself is much more variable.

I'm sure you wouldn't accept it if I said, "I've measured sharpness with jigs recently and found that it produced a much higher level of sharpness". Your reply I would bet would be... let's see the numbers.

I would be interested in how you were measuring it and what you meant by significant, but quoting numbers would not make the arguement more definate because if you are willing to make up an arguement to decieve then you can obviously fabricate numbers. Arguements have to be supported by external verification or be consistent with known principles, supporting facts from sources that are not you. This is why in any published paper you will find lists of references to show what is being stated agrees (or contends) what others have seen.

... so I could sharpen a knife at any angle, and as long as I account for burr removal etc. the knife will be equally sharp? (Hope that made sense).

Yes, that would be how I would define it, in the limit that the binding ability of materials goes to zero, a measurement of cutting ability will reduce to sharpness. Some people don't consider this effect and thus will say a 10 degree edge is sharper because it cuts better than a 20 degree edge. However that defination is severely flawed. I can take a 10 degree edge and then draw it across a stone so it won't slice newsprint however it will still whittle wood better than a 20 degree bevel but would you say it was actually sharper? If for example I converted a thick sabre/hollow to a high flat but never touched the edge it would cut better but would you say I sharpened it?

-Cliff

 

[cbwx34]

Cliff,

Not looking for more definitive, just looking to understand what you're saying a bit better. Of course anything can be fabricated, that's not the point of the request.

I understand what you said in the last part, but in my mind there's go to be more to it. So, taking out the binding ability of the material, doesn't angle still have to play some role in the level of sharpness? Of course I could take a 10 deg edge and dull it, but then it's not really a sharpened 10 deg. edge. So, 2 questions... all things being equal would a 10 deg edge be sharper, or is is still not part of the definition as you see it? The 2nd question... doesn't there have to be a limit to the angle? In other words, how large of an angle can you sharpen at, before it would be taken into consideration?

cbw

 

[Cliff Stamp]

... just looking to understand what you're saying a bit better.

When I started doing freehand for the comparisons I compared the sharpness against jigs. On light cotton for example, optimal sharpness from jigs was ~0.25 cm of travel under a given tension. I was easily able to obtain this freehand and later pushed past it. I tend to find now that freehand is actually easier to obtain a higher sharpness due to things like body mechanics and larger stones. But again I am multi-beveling which minimizes the need for angle control.

So, 2 questions... all things being equal would a 10 deg edge be sharper, or is is still not part of the definition as you see it?

Assuming the steel can handle the angle, if both were optimally sharpened the width and condition of the apex would be the same, 0.1 microns or so for a fine polish.

The 2nd question... doesn't there have to be a limit to the angle? In other words, how large of an angle can you sharpen at, before it would be taken into consideration?

As with most things there are usually complications if you look deep enough at the details. On really coarse steels the edge will break apart at low angles, this is a small refinement and not what you would focus on. The first thing is to separate sharpness and cutting ability which Swaim was one of the first to do. It models like :

Cutting ability = A(edge angle)^a + B(sharpness)^b + C(edge width)^c+D(primary grind angle)^d+E(stock thickness)^e

There are also cross terms but they are not first order dominant. The size of the coefficients changes dramatically. The power of the edge angle is close to one as is the power of the sharpness. However the other power are generally << 1.

So if you take an edge from 20 -> 10 you expect the cutting ability to about double (depends on the medium) but if you take the edge width from 0.075 (scandinavian bevels) to 0.05 (Wilson) you don't expect a 15 times increase in cutting ability, because c is << 1.

The A,B,C coefficients say how much of the property is important, they depend on the type of cutting. For example chopping wood isn't very sensitive to sharpness so B is small but it is strongly dependent on the overall thickness of the blade so D & E are large, however when cutting thin ropes D & E are <<1 and even C is very small.

-Cliff

 

[bbcmat]

The effect of stone wear can be minimized by applying the offset in stone thickness directly to the height of the stone pivot arm - this difference is easily estimated by the change in the blade ramp, one stone to the next.

You would have to be very skilled to repeat a new angle with EdgePro consistancy side to side and stone to stone - by hand - on an assortment of knife shapes and lengths. Uncompensated stone wear can account for up to 0.6 degrees of angle shift (est) - that's a small variation, but will make your life harder with high RC blades / single wide bevels at fine finishes. The device was never intended to replace a CNC machining center.

Once you have your database of knives (recording cut angle, transition angle, final stone, table rest position, clip Y/N, and comments) - then tuning up blades you've reworked is easy, consistant, and evolutionary (based on your inspection after being in service). My wife raved about this mickey mouse IKEA veggie knife to her friends - now I have an angle for each user based on the sort of wear I observed after resharpening their IKEA specials.

I don't have that skill freehand, everything gets ground to my eyeball and 3 finger test. Great for my rough stuff - not comfortable doing that on other peoples tools.

MAT

 

[Cliff Stamp]

I have an angle for each user based on the sort of wear I observed after resharpening their IKEA specials.

Details, angle/use?

-Cliff