How to sharpen a head knife

[Rawhide]

To all:

I have had several requests to explain how I sharpen my head knives. I am by far not an expert, but here is how I do it, and it works for me. There was a thread where I addressed this before the crash of 07.

Below is a link to the tutorial that most gracious Johanna has created.

Please feel free to contact me if you have questions. I hope this is something useful.

Tool on!

Marlon

How to sharpen a head knife

https://leatherworker.net/sharpenheadknife.htm

Edited August 26, 2019 by Northmount
fixed URL for secure server

[cybertracy]

Thank you so much Marlon (and Johanna) for this tutorial. I've gotten my knife close but can't seem to gain any ground, this should really help.

[bruce johnson]

Marlon,

Thanks for the tutorial. I like the tip of stacking coins to establish an angle. A penny is working for my pocket knife. I run a a little thinner edge than you do on the round knife - mine is about a 26 cent angle. Great tip there, as well as the sharpening instructions. Thanks again.

[Randyc]

Marlon and Johanna

Thanks for the sharpening instructions. I really needed them.

Randy

[Rawhide]

Great. I'm glad this is useful to you.

Bruce, do you like about a 15 to 18 degree angle? What are some of the advantages for your thinner angle? I'm just asking, because I someone may be thinking it!

Marlon

[whinewine]

Good post, Marlon. I've saved it and printed it out. Thanks. russ

[Rawhide]

You're most welcome Russ. There is also a link on the "More Tips & Tricks" page which is linked on the main page.

Marlon

[bruce johnson]

Great. I'm glad this is useful to you.

Bruce, do you like about a 15 to 18 degree angle? What are some of the advantages for your thinner angle? I'm just asking, because I someone may be thinking it!

Marlon

Marlon,

I have never measured an angle, that is why the coin deal seems high-tech and very handy to me. I always went by feel. I like a little thinner knife than some. I don't like a lot of "shoulder" on the blade. Some knives are thicker and then bevel down in the 3/4" to the edge. They tended to drag for me as I got into deeper cuts blocking out. Trimming strips where the trimming fell away not so much. I took a knife to the real extreme once and the edge got so thin it rolled after a short time. I learned from Herb French's book on leather tool sharpening about a secondary bevel. Basically make the very edge a little steeper bevel to prevent the rolling. This has served me well now.

[cjbleather]

Marion and Bruce, First Marion, Thanks fior the tutorial. It is great.

Now Bruce, Where does one get the French book?

Now both of you. I see the theory and possible ease behind the stack of quarters or one quarter and a penny. But, this doesn't make the same angle every time. You can still lay the knife on the edge and tilt it one way or another and vary the angle. How do you get the feel to have the right angle? Gosh I hope that I phrased this right! I am not critizing, I am just trying to find out. Keeping a steady angle throughout the sharpening process, I believe, is critical. Thanks again to the both of you for your input. Carlb

[Rawhide]

CBJ,

There is some finesse to "feeling" the right angle. Unfortunately, there aren't many jigs out there that will help you maintain that angle. You could mabe make a wedge at the proper angle and rubber cement it to the side of your blade if you don't think you can hold it. Problem is you'll be grinding it as well. I know quarters vary and these therefore your angle will too, but keep in mind, it's just an approximation. You could also fold a piece of paper like you're making a paper airplane, then fold it the same way again and it will give you a 22.5 degree angle.

Once you establish what the angle is, It's not very difficult to keep the blade at that angle. Most people probably do it by referencing the distance of the ferrule from the top of the stone/hone. If that distance is about an inch, most people can see the difference between that inch and an inch & a half, and know whether or not they are maintaining that angle.

I hope this answers you question. Bruce may have a better response.

Marlon

[bruce johnson]

Carl,

I did a little sharpening last night, and found the stack of coins gives me a starting angle. I always just kind of eyeballed it before. This just gives me more of a constant to make sure a new knife is the same as my favorites. Obviously blade width will play a part in changing the angles too.

Herb French is from Sheridan WY. Sheridan phone directory probably has him. They sell the books at Sheridan Leather Outfitters too. They cost about $10. Herb sharpens tools for folks in that area, does some mail-order sharpening, and may still be doing the metal work for Bob Douglas too. The book is pretty good, and some nice little tips about power sharpening, hand sharpening, and some of the special nuances of sharpening leather tools.

[Hilly]

Marlon, thanks for the little tutorial. I hope some day soon I will get the nerve to try to touch up my new head knife on a stone. Seems that every time I've ever tried to sharpen something on a stone, it comes out duller than when I started. I'm sorta scared to try it.

I've already had it get a little dull, and I pulled it through a ceramic sharpener a couple times on each side of the blade. It shaved hairs off my arm afterwards. I don't know it will work in the long run, though. Maybe I've found a shortcut? I'll keep you informed.

Hilly

[cjbleather]

Thanks Bruce and Marion. I guess I am a too logical type of person. Or, is it the engineering coming out. But, I don't feel too comfortable with the rch approach. After I sent the first email, it dawned on me that one way I could figure out the conumdrum ( actually the blade extension beyond the quarters) is to use the tangent of the angle. The height of the quarters would be the opposite side, while the adjacent side (Which I am trying to find out) could be determined. Now then, I have to get my engineering book out to find the tangent of a 20 degree angle. Carlb

[Rawhide]

Thanks Bruce and Marion. I guess I am a too logical type of person. Or, is it the engineering coming out. But, I don't feel too comfortable with the rch approach. After I sent the first email, it dawned on me that one way I could figure out the conumdrum ( actually the blade extension beyond the quarters) is to use the tangent of the angle. The height of the quarters would be the opposite side, while the adjacent side (Which I am trying to find out) could be determined. Now then, I have to get my engineering book out to find the tangent of a 20 degree angle. Carlb

Tanget = opp over adjacent? Therefore, tan 20 = quarter stack/ x , then x = quarter stack / tan 20.

(I'm an NGNEER, too!)

Marlon

Edited March 13, 2008 by Rawhide

[tonyc1]

Tanget = opp over adjacent? Therefore, tan 20 = quarter stack/ x , then x = quarter stack / tan 20.

(I'm an NGNEER, too!)

Marlon

You blokes speak an entirely diff. language!!!

Tony.

[Rawhide]

it's not really as hard as people think.

[cjbleather]

Marion, Off hand or easily available to you, what is the tan of 20 degrees? Thanks Carlb

PS I haven't found my engineering formula/table book yet. I can't even remember what we used to call this book as we went through school. yach for my memory.

[Art]

.3639?

And it was the CRC Standard Math Tables, that was many many moons ago.

Art

Marion, Off hand or easily available to you, what is the tan of 20 degrees? Thanks Carlb

PS I haven't found my engineering formula/table book yet. I can't even remember what we used to call this book as we went through school. yach for my memory.

[Rawhide]

.3639?

And it was the CRC Standard Math Tables, that was many many moons ago.

Art

Yup, exactly what Art said.

[Sharpshooter]

Now then, I have to get my engineering book out to find the tangent of a 20 degree angle. Carlb

Google is a wonderful tool, better than any calculator or trig textbook..... Type in "tangent of 20 degrees" ...

Ok, now since I jumped in being a wiseguy, I have a question....

Why not a convex edge on a head knife? I've been working with knives and knifemakers for a long time and have found that a convex edge is far and away better than a bevel in every case. I made my headknife and convexed it from the beginning so I have no basis for comparison.

As far as I can tell, the knife works perfectly, cuts around curves, skives well and stays sharp; is there something I'm missing?

[Art]

Hi Sharp,

The old Convex -- hollow ground -- straight bevel controversy again? Been there done that on the knife-list 10 or more years ago. Convex is great, I like meat behind my edge. However, that is not an easy edge for the average leatherworker to profile, and the newer head knives are getting thinner and thinner to the point that the Convex is getting darned near impossible, not quite, but darned near. While you and I probably have a Bader or a Burr-King where you can get a long run of belt to effectively produce the edge (although the Japanese used to do it with a rock) the average leatherworker doesn't and the hollow or straight is much easier with readily available tools, and very easy to maintain. I do agree that convex is better if you have a thick enough blade to pull it off, the J.Cook blades would be candidates for a convex edge, and even the CSO blades could be done to effect. The last .030-.060 of most convex edges are straight bevels anyway.

Art

Google is a wonderful tool, better than any calculator or trig textbook..... Type in "tangent of 20 degrees" ...

Ok, now since I jumped in being a wiseguy, I have a question....

Why not a convex edge on a head knife? I've been working with knives and knifemakers for a long time and have found that a convex edge is far and away better than a bevel in every case. I made my headknife and convexed it from the beginning so I have no basis for comparison.

As far as I can tell, the knife works perfectly, cuts around curves, skives well and stays sharp; is there something I'm missing?

[Sharpshooter]

Hi Sharp,

The old Convex -- hollow ground -- straight bevel controversy again? Been there done that on the knife-list 10 or more years ago. Convex is great, I like meat behind my edge. However, that is not an easy edge for the average leatherworker to profile, and the newer head knives are getting thinner and thinner to the point that the Convex is getting darned near impossible, not quite, but darned near. While you and I probably have a Bader or a Burr-King where you can get a long run of belt to effectively produce the edge (although the Japanese used to do it with a rock) the average leatherworker doesn't and the hollow or straight is much easier with readily available tools, and very easy to maintain. I do agree that convex is better if you have a thick enough blade to pull it off, the J.Cook blades would be candidates for a convex edge, and even the CSO blades could be done to effect. The last .030-.060 of most convex edges are straight bevels anyway.

Art

Thanks for the answer Art, A while back I did a tutorial on sharpening convex edges.

The same technique can be used to convex a bevel ground blade.

Here's the link. I do have the luxury of having a full fledged knife factory on the other side of the building so I can jump on a buffer to freshen up the edge but the technique in the tutorial works just as well.

I need to make another head knife since my crew has discovered mine they all want one. Old tool technology just never dies...

[TwinOaks]

I'll second the notion that a convex edge is harder for the layperson to maintain.

Now, for the engineers here.....what in hades does driving a train have to do with figurin' out how to sharpen a knife????????

[JAM]

I see by the dates on earlier posts that I am way late in discovering this thread, and the sharpening info is terrific and so useful. I wanted to add my two-cents' worth about honing to keep that razor edge on the blade.

To keep my knives cutting leather like it's butter, I use a hard felt wheel (leevalley.com) dressed with the green compound, on a buffer that's mounted backwards (so the wheel is spinning away from me over the top). It takes a little practice to get the knack of it - but I eyeball the angle (with practice you just know how to stand and hold the knife to get the angle you need so you don't need to eyeball it anymore) and keep the edge of the blade sighted down over the wheel's spindle (if that makes sense) so I have good pressure directly on the edge of the blade. Then I use one or two fingers of my free hand on the body of the blade to lightly press the edge of the blade onto the wheel while I move it from one corner to the other. I hone my swivel knife blades the same way.

[Rawhide]

I see by the dates on earlier posts that I am way late in discovering this thread, and the sharpening info is terrific and so useful. I wanted to add my two-cents' worth about honing to keep that razor edge on the blade.

To keep my knives cutting leather like it's butter, I use a hard felt wheel (leevalley.com) dressed with the green compound, on a buffer that's mounted backwards (so the wheel is spinning away from me over the top). It takes a little practice to get the knack of it - but I eyeball the angle (with practice you just know how to stand and hold the knife to get the angle you need so you don't need to eyeball it anymore) and keep the edge of the blade sighted down over the wheel's spindle (if that makes sense) so I have good pressure directly on the edge of the blade. Then I use one or two fingers of my free hand on the body of the blade to lightly press the edge of the blade onto the wheel while I move it from one corner to the other. I hone my swivel knife blades the same way.

Good info Jam.

I actually use the cardboard paper wheels to keep the edge honed when I'm at home, and I use the four sided strop to fix it up when I'm away from home. However, I wrote the tutorial for those folks that don't have the grinder/buffer to use. This is the old manual way to do it.

Thanks for the additional info.