How do you know what angle you are sharpening at?

B

bgentry

Joined
Aug 3, 2009
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With guided systems, obviously the angle they use is what you get. This is true of Lansky, Sharpmaker, etc (though I understand that Lansky's markings are off by a few degrees).

But what about hand sharpening? For many years I simply tried to find the angle already on the blade, and tried to refine it to get a better (thinner and more polished) edge. This worked ok and I got shaving sharp edges most of the time, but not always.

A few years ago, I read about how to micro-bevel (thank you Chad Ward!), and was actually successful. Confession time: Though I think I have a fairly good ability to hold the same angle on a blade from stroke to stroke, I have very little ability to estimate the angle I'm using. Nor can I produce the same angle from day to day. So I used Chad's (seemingly silly) paper airplane trick to fold a few pieces of paper into wedges of 22.5 degrees and 15 degrees.

Using those wedges, I can position my knife blade at (approximately) one of those angles, and hold it pretty well for a while. I check periodically, using the wedge as a reference to make sure I'm staying approximately at the right angle. I feel a little silly holding a knife blade on a wedge of paper, but it *does* work for me.

Using a 15 degree secondary bevel and a 20 (or 22.5) degree primary, I'm getting some pretty impressive (to me) sharpness out of good knives. But I'm "cheating" by using a reference.

Further, if I said to my self, "Self, why don't you try putting a 12 degree secondary and a 17 degree primary angle on that knife over there with the good hard super steel?", I wouldn't know where those angles were. I could estimate using paper wedges, or try to build wooden wedges using a protractor and wood working tools or something I guess.

Obviously an Apex would make this fairly easy. A rod system (Lansky) would make this easy too (except that the angles aren't as marked).

But from some reading I've done here, people talk about going down to 10 degrees per side, or 17, or 20 or... So how are most people determining this? Guided systems? Jigs? Paper wedges? Incredible super angle determining sense imparted by divine forces at birth? [:)]

Discuss.

Brian.
 
Bgentry,The paper folding that Chad and others suggest works.But I took the time as you mentioned, got my protractor out and some wood and measured off and cut several wedges and labeled them their approiate angle.So, while sharpening I can check it to see if I'm close.But good guides are useful.Still,I think the exact angle is not as important
as a consistent angle somewhere near 15-17*.Perhaps more for a camp/survival knife 18-20*. But makes for academic discussion.Just my 2cents.DM
 
If you're freehanding convex edges, then measuring the angle would not be very useful. You can take a picture with a camera and measure it based on the picture at 100% crop. Still, you can't correlate convex edges with flat edges.

My EdgePro has calibrated and marked angles down to 7.5 degrees per side. I made some edges and measured them with my precision caliper and microscope. Then I calculated the angle based on trig functions.
 
cotdt said:
If you're freehanding convex edges, then measuring the angle would not be very useful. You can take a picture with a camera and measure it based on the picture at 100% crop. Still, you can't correlate convex edges with flat edges.

My EdgePro has calibrated and marked angles down to 7.5 degrees per side. I made some edges and measured them with my precision caliper and microscope. Then I calculated the angle based on trig functions.
Click to expand...

Wow, you use a Precision Caliper and a Microscope plus Trigonometry to sharpen knives! You must really be into getting a super sharp blade.

I use one of the paper wheel systems and I've found out with some practice where to hold the blade for a very nice sharp knife with about 2-3 minutes work.

I'm glad I have not become hooked on getting these scary sharp edges people talk about.
 
cdhumiston said:
Wow, you use a Precision Caliper and a Microscope plus Trigonometry to sharpen knives! You must really be into getting a super sharp blade.

I use one of the paper wheel systems and I've found out with some practice where to hold the blade for a very nice sharp knife with about 2-3 minutes work.

I'm glad I have not become hooked on getting these scary sharp edges people talk about.
Click to expand...

You've obviously never reads posts by knifenut1013! His microscope is better than mine.

If I needed a sharp edge quickly, a sandpaper-on-mousepad can get a sharp edge in a few minutes as well, but it's no fun. And most people could not afford your paper wheel system.
 
Might not help, but for what it is worth. What I do, is consider what a knife is cutting like and how I am using it. Judge from there if the angle is correct, or needs to be adjusted, then go from from there. Just what works for me.
 
I do the trig as well, I then try to as closely as possible match the result in millimeters using stacked coins.
 
I prop my stones up to my desired angle (I use a carpenter's tool to lay on the stone and measure the angle), then hold the knife parallel to the table to get as close as possible to what I want. I usually backbevel at 10 per side on most VG-10/S30V/154CM type steels, then microbevel between 15 and 20 degrees. On ZDP 189 and M4 I usually go a bit thinner on the backbevel and a tad thinner than the other steels on the microbevels (my microbevels are usually 10-15 per side with ZDP and M4, only 10 per side on my lighter duty knives and 15 per side on my harder use ZDP knives).

Mike
 
I don't really measure the angle when I sharpen, I just sharpen it.
After free handing for around 20-25 years, I just know what works for me and what won't.
Most of the time I hold the stone in 1 hand and the knife in the other and move both.
 
I sharpen freehand and haven’t a clue what the exact angle are. I figure out whatever angle works best for each knife, overtime by progressively sharpening it at more acute angle than the previous time – until the edge fails to get the job done.
 
I do something similar to Gunmike's approach, only I have the stone held in a vise or jig at the desired angle off vertical. Personally I find it much easier to keep the blade vertical during the full range of motion when sharpening, rather than horizontal -- probably from years of using CrockSticks and Sharpmaker.

But that's only when I need the angle to be somewhat exact, such as when doing edge retention testing. Much of the time I freehand the primary/relief bevel, so long as it comes out somewhere in the 10-12 degree/side range is good, and then finish sharpen with a microbevel of 17-20 degrees. For most uses, it's only the microbevel that needs to be somewhat exact, or at least "obtuse enough" depending on the steel.

Of course those exact edge bevels look pretty, which may be reason enough.
 
Interesting range of responses. Everything from "yes I use a guide" to "I use a jig" to "I just do what works for me and my knife". Now I feel less silly about my paper wedges. :)

Gunmike and DogOfWar: What do you use to measure your angles? Mike, what do you "prop your stones up" with? Just curious.

Thanks for all the replies.

Brian.
 
I can't measure nor hold an angle except the current angle of the bevels I'm sharpening. If the bevels are big enough, I put them on the stone at a slightly lower angle, then I start the stroke while "tipping" the angle forward until I feel some resistance. That's my indicator that I'm at the same angle as the bevels.
 
This helps a little: For 20 degrees per side the height of the centerline of the spine above the stone is a third of the blade width. For 15 degrees per side the height is a fourth of the blade width.
 
bgentry said:
Interesting range of responses. Everything from "yes I use a guide" to "I use a jig" to "I just do what works for me and my knife". Now I feel less silly about my paper wedges. :)

Gunmike and DogOfWar: What do you use to measure your angles? Mike, what do you "prop your stones up" with? Just curious.

Thanks for all the replies.

Brian.
Click to expand...

I use a small angle reader from Home Depot (see the top of page 3 of the Microbevel thread stickied at the top of this subforum for a pic) to measure my angles. I use the backsplash of my counter as a stop, and use my other stones, like my Spyderco stones in their factory supplied cases, to prop up the end of my rubber stone holder on with those Spyderco cases backed up to the backsplash so they can't move as I sharpen. I have some pics of this at home, I should post them as it is easy to see the somplicity in a picture yet hard to explain. I have a whole series of pics of a complete sharpening session, and I am probably going to do a quick write up on how I sharpen and throw those pics in so you can both see my method and see the edge progress through the grits.

Mike
 
Hawkings said:
I don't really measure the angle when I sharpen, I just sharpen it.
After free handing for around 20-25 years, I just know what works for me and what won't.
Most of the time I hold the stone in 1 hand and the knife in the other and move both.
Click to expand...
+1:thumbup:
 
bgentry said:
Gunmike and DogOfWar: What do you use to measure your angles?
Click to expand...
Originally I just used an ordinary protractor, but after a while I cut out some cardboard angle templates with the angles I use the most -- 10 deg, 12 deg, 15 deg, etc.

Here's a pic of the simple wooden jig I made to hold a 2" wide stone:

sharpening-jig.jpg


At first I just clamped the stone in the vise. But the jig, because it projects out and away from the workbench, gives me better clearance for working both sides of the blade. Either way, you can see how you can use a protractor, or angle template, to measure the angle of the stone.

BTW I know in other threads here on BFC guys have posted pictures of using a PanaVise in the same way, maybe somebody has a link.

.

.
 
Dog of War said:
BTW I know in other threads here on BFC guys have posted pictures of using a PanaVise in the same way, maybe somebody has a link.
Click to expand...

I'm not sure about here, but I found a thread on another forum from a guy named Ken that did a series of Panavise setups. They were pretty interesting. The first one is on the first page of the thread here.

Seems like a pretty accurate setup, though a bit involved. I think I'll experiment with propping up stones and some way of measuring angles. That inclineometer seems like it might be good to have. Interesting stuff.

Brian.
 
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