Work Sharp Ken Onion - what is the real angle when using the guide?

[ZT0566FDEBW]

This might seem like a dumb question, but the answer, I believe, isn't as obvious as it seems.

I've been using a couple of different Work Sharp systems of late. I've had the WSKTKO for a couple of years now, and had almost walked away from it entirely, as I found I'd been causing more damage to my blades than helping them - usually from running too high a speed, I'd guess. Recently got the Guided Sharpening System - the diamond platform that pivots, with the additional "extras" kit that includes two more diamond plate grits and a strop plate - and have had some decent success with getting even bevels, biting edges, and the like. Today was working on a blade I'd previously messed up with the Ken Onion and wasn't really getting anywhere with apexing, so thought I'd use the KO again to get a quick burr, setting the guide angle to match the 17 degree guide I'd been using with the manual system.

Imagine my surprise that, when using the sharpie, I kept having to dial up the angle to 25 degrees per side to hit the edge.

I'm wondering if this is due to the convex edge nature of the KO. Different blade grinds seem to require more or less "adjustment" to hit the edge from my supposed "constant" angle from the manual system.

Just was wondering if anyone else using the KO had found the angle guide setting is producing different than expected edge angles?

Thanks!

 

[bucketstove]

20+5 = 25 17+8=25

This might seem like a dumb question, but the answer, I believe, isn't as obvious as it seems.

I've been using a couple of different Work Sharp systems of late. I've had the WSKTKO for a couple of years now, and had almost walked away from it entirely, as I found I'd been causing more damage to my blades than helping them - usually from running too high a speed, I'd guess. Recently got the Guided Sharpening System - the diamond platform that pivots, with the additional "extras" kit that includes two more diamond plate grits and a strop plate - and have had some decent success with getting even bevels, biting edges, and the like. Today was working on a blade I'd previously messed up with the Ken Onion and wasn't really getting anywhere with apexing, so thought I'd use the KO again to get a quick burr, setting the guide angle to match the 17 degree guide I'd been using with the manual system.

Imagine my surprise that, when using the sharpie, I kept having to dial up the angle to 25 degrees per side to hit the edge.

I'm wondering if this is due to the convex edge nature of the KO. Different blade grinds seem to require more or less "adjustment" to hit the edge from my supposed "constant" angle from the manual system.

Just was wondering if anyone else using the KO had found the angle guide setting is producing different than expected edge angles?

Thanks!

Hi,
I don't have a KO
but I have been using wedges since starting to sharpen in 2015,
If you knives dont have a primary grind, a blade grind,
if they're just flat pieces of steel ,
except for the edge,
like a paring knife
when you lay the blade flats against a 17 degree wedge,
you're getting 17 degrees per side edge

but if the blade has a blade grind of 3 degrees to 6 degrees
(thats 99% of blades with primary grinds)
the edge angle you're getting with a 17dps wedge is 20-23 dps (17+3 to 17+6)
with the 20dps wedge thats 23-26 degrees per side (20+3 to 20+6)


Not sure how easy it would be to switch out the angle guides on the WSGSS
but you'd notice the better performance with 7 degree wedge and 10 degree wedge
10-12 dps ( 7+3 to 7+6 ) for not-choppers
13-16 dps ( 10+3 to 10+6 ) for choppers
consider that under 15 dps edge can chop bones And 12 dps edge can still shaves/whittles beard hair after 1000 slices of hardwood ,

 

[bgentry]

I would guess that it's some combination of:

1. The belt "slop and wiggle" hitting higher up on the blade grind than you expect.

and/or

2. When using the hand guided system, you may be raising the blade up to a higher angle than the wedge reference that you are using.

I haven't measured the angle on the WSKO guide, but I sorta remember someone doing it a long time ago and finding it to be very close. But my memory of this is fuzzy and I'm not sure I actually saw this. <shrug>

Either way, the exact angle really doesn't matter much. It's just academic. The consistency of the angle DEFINITELY matters.

Brian.

 

[cbwx34]

I'm wondering if this is due to the convex edge nature of the KO. Different blade grinds seem to require more or less "adjustment" to hit the edge from my supposed "constant" angle from the manual system.

Just was wondering if anyone else using the KO had found the angle guide setting is producing different than expected edge angles?

Thanks!

To answer this part... the angles are pretty accurate... there's even a picture from WS that shows the angle guide actually compensate a bit for the belt slack...

... and it's easy enough to check.

So, as others have indicated... must be another reason you're seeing such a difference.

 

[Pila]

20+5 = 25 17+8=25

While the basic premise stands and is crucial for understanding angles regardles of device used, math is completely wrong for the WSKTKO! The angle wedge goes between the knife and the stone, lifting the knife centerline away from the abrasive, hence the + sign above. The WSKTKO does the completely opposite thing. Plus, with the convex grind, math gets more complicated as there is no single flat plane to be measured.

So, for WSKTKO: If you place a 2 mm thick knife (at the guide contact point) into a 15 deg angled guide, you are actually removing (minus sign) a bit over 2 deg from the set 15 deg because at WSKTKO a knife is between the angle guide and the abrasive so any thicknes of the knife will move the knife toward the abrasive therefore reducing the angle making it more acute. So, for WSKTKO: 15 deg - 2 deg = 13 deg.

As for the convex edge angle guide precison, I can only compare the feel of a japanese knife sharpened OOB (originally) at 15 dps with the same knife done at WSKTKO at 15 deg. It needs a singe pass quick on a rough grit to raise a burr and the knife cuts even better than the orignal edge. Subjective, but I can not make it more precise.

 

[cbwx34]

While the basic premise stands and is crucial for understanding angles regardles of device used, math is completely wrong for the WSKTKO! The angle wedge goes between the knife and the stone, lifting the knife centerline away from the abrasive, hence the + sign above. The WSKTKO does the completely opposite thing. Plus, with the convex grind, math gets more complicated as there is no single flat plane to be measured.

So, for WSKTKO: If you place a 2 mm thick knife (at the guide contact point) into a 15 deg angled guide, you are actually removing (minus sign) a bit over 2 deg from the set 15 deg because at WSKTKO a knife is between the angle guide and the abrasive so any thicknes of the knife will move the knife toward the abrasive therefore reducing the angle making it more acute. So, for WSKTKO: 15 deg - 2 deg = 13 deg.

As for the convex edge angle guide precison, I can only compare the feel of a japanese knife sharpened OOB (originally) at 15 dps with the same knife done at WSKTKO at 15 deg. It needs a singe pass quick on a rough grit to raise a burr and the knife cuts even better than the orignal edge. Subjective, but I can not make it more precise.

Guess I need a picture or sketch... I don't get this.

 

[Pila]

Guess I need a picture or sketch... I don't get this.

If you quoted what confuses you... So I try to guess.

There is a difference if the knife is lying on the wedge which is on the stone. Knife thicknes causes angle to be added: say 15 goes to 17 deg.

Oposite goes for: there is a guide, then the knife leaned on it and the sharpening surface is on the oposite side of the guide. Knife between them moves its center closer to the sharpener. e.g. 15 deg becomes 13.

If the angle is correct for the wedge / guide empty, a 2 mm thick knife will offset the centerline for half of its thickness depending on the contact points.

Basic trigonometry.

 

[cbwx34]

If you quoted what confuses you... So I try to guess.

There is a difference if the knife is lying on the wedge which is on the stone. Knife thicknes causes angle to be added: say 15 goes to 17 deg.

Oposite goes for: there is a guide, then the knife leaned on it and the sharpening surface is on the oposite side of the guide. Knife between them moves its center closer to the sharpener. e.g. 15 deg becomes 13.

If the angle is correct for the wedge / guide empty, a 2 mm thick knife will offset the centerline for half of its thickness depending on the contact points.

Basic trigonometry.

I think you're confusing what happens with guided sharpeners like the W.E., Edge Pro, KME, etc. In those cases, the thickness of the blade can change the angle, because the blade is part of the triangle created.

But, thickness doesn't matter on the WorkSharp. If you look at the picture I posted earlier... the guide is vertical, and the belt runs 20° in relation to it. (I'm leaving convex out for simplicity). So, no matter how thick the blade, if you hold it vertical, the belt will hit it at 20°. (The difference, of course, is how far down you can insert the blade).

Now, if you talk blade taper (taper from spine to edge... what bucketstove was talking about), and you put that up against the guide, then the angle would decrease (because you're no longer holding it vertical). But thickness has nothing to do with that.

Unlike the sharpeners I mentioned earlier, where the blade is part of a triangle, in this case the blade is "independent" of the triangle created. So, "basic trigonometry" doesn't really apply... (if I understand what you're saying).... you're just holding a blade vertical against a belt running at a set angle. (And no matter what angle you set the guide, you're just holding the blade in relation to the angle between the guide and the belt, as long as you don't use the blade taper to do it, it's the same result).

 

[Mr.Wizard]

I think Pila is assuming that you hold the blade flat against the guide, where blade taper matters as you note. Blade thickness being interrelated with taper one could phrase it in those terms.

 

[CasePeanut]

TL;DR - just follow the sage advice of B bgentry and keep your angles consistent!

The OP is really asking about the difference between the angle guides on the WSGSS and WSKO.

I own and like both products, but I find it hard to maintain the angle of the WSGSS guides on the plate. There is a tiny ‘jump’ that your hand has to make as it pulls off the guide and onto the plate. My hand wobbles when I make the jump every single time unless I am completely focused.

It’s something I don’t experience with an angle guide rubberbanded to a regular benchstone. The guides and the entire system of the WSGSS is fantastic for learning how to freehand. It was really critical in teaching me some of the skills and techniques required for freehand sharpening on a benchstone, but I feel like that one little gap keeps the system with the guides on from reaching VERY sharp edges.

The angle guides on the WSKO are a different animal due to the vertical pull-through mechanics of the WSKO. I haven’t used the KO guides much (I freehand with the BGA - see B bgentry youtube videos for a lesson) but overall the WSKO seems like a more forgiving movement with less potential for the user to drastically change the angle.

Overall, if you’ve made it far enough to get decent edges on both the WSKO and the WSGSS then you are ready to remove the guides and start freehanding on both systems. Start with some cheap knives and lots of sharpie. You’ll have awesome edges with just a few hours practice.

 

[DDDYLN]

Does anyone know if I can get a 10 degree angle on my Ken Onion? My high end kitchen knives are mostly 15 degrees. However, the Santoku knife has a 10 degree angle. The lowest angle on the Ken onion blade guide is 15 degrees.

 

[Another Shepherd]

When I sharpen kitchen knives with the Ken Onion, I set the angle to 15 degrees. Since the resulting bevel is convex, the angle varies from about 10 degrees at the top of the bevel to 20 degrees near the apex. Over the entire bevel, the angle averages out to about 15 degrees.