Knife sharpening techniques for all

[Ooh-Rah]

Question - what is the difference between a knife needing to be sharpened vs. just needing a touch-up w/a steel? After this thread started I realized how much I don't know, and decided to run my ZT against a steel a few times. It was razor sharp again!

Am I damaging the blade by doing this?

 

[compforce]

Question - what is the difference between a knife needing to be sharpened vs. just needing a touch-up w/a steel? After this thread started I realized how much I don't know, and decided to run my ZT against a steel a few times. It was razor sharp again!

Am I damaging the blade by doing this?

As you cut with the knife, the edge starts to roll. If you do it long enough without touching it up, you actually end up with a wire edge. (Science types like X-SF will also say that the molecules get out of alignment). You use a steel to move the edge back to straight while removing any microscopic imperfections caused by use. The steel weakens a slight bit each time you do this. It's just like bending a paperclip back and forth, each time you do it, it gets weaker until it finally breaks. Sharpening takes off the very edge off the knife, which is the weakest part both because it's the thinnest and the part that gets bent the most. So sharpening effectively makes your edge stronger than it was by removing the weak part. You should sharpen the knife initially, then use a steel until the knife is losing it's edge quickly and then sharpen it again. For my kitchen knives, I hone them every time I pick them up to use them and I sharpen them about every 2-3 months.

The other thing the honing steel is "supposed" to do is to realign the molecules and to remove any metal dust from the edge. It does it through magnetism. Your steel should stick magnetically to iron. If it doesn't, you aren't using it enough and/or it's a cheaper one. In either case you aren't getting the full benefit. Make sure your steel has a magnetic charge!

Steel hones, which is a non-destructive process. Sharpening removes metal. If you only sharpen, you are shortening the life of the blade significantly.

 

[Barbarian]

As you cut with the knife, the edge starts to roll. If you do it long enough without touching it up, you actually end up with a wire edge. (Science types like X-SF will also say that the molecules get out of alignment). You use a steel to move the edge back to straight while removing any microscopic imperfections caused by use. The steel weakens a slight bit each time you do this. It's just like bending a paperclip back and forth, each time you do it, it gets weaker until it finally breaks. Sharpening takes off the very edge off the knife, which is the weakest part both because it's the thinnest and the part that gets bent the most. So sharpening effectively makes your edge stronger than it was by removing the weak part. You should sharpen the knife initially, then use a steel until the knife is losing it's edge quickly and then sharpen it again. For my kitchen knives, I hone them every time I pick them up to use them and I sharpen them about every 2-3 months.

The other thing the honing steel is "supposed" to do is to realign the molecules and to remove any metal dust from the edge. It does it through magnetism. Your steel should stick magnetically to iron. If it doesn't, you aren't using it enough and/or it's a cheaper one. In either case you aren't getting the full benefit. Make sure your steel has a magnetic charge!

Steel hones, which is a non-destructive process. Sharpening removes metal. If you only sharpen, you are shortening the life of the blade significantly.

This is correct. Honing with a steel realigns the carbides at the edge, and will not damage your knives.

 

[x SF med]

Any new questions before we head on in to more discussion on sharpening? I'll try to post more pictures for our Marine Bretheren, we've got a lot of words here and we know they like pictures.:wall:

 

[x SF med]

Here is a link to a pretty good terminology/knife anatomy discussion written by Jay Fisher, a well known custom knifemaker. there is a lot of information here. http://www.jayfisher.com/Knife_Anat...tomy_Knife_Parts_Knife_Names_Knife_Components


Here's a link to a discussion of cutting edge angles: http://www.sharpeningsupplies.com/Detailed-Discussion-on-Knife-Sharpening-Angles-W28.aspx

 

[Barbarian]

Sharpening 1:

First, if you are learning to sharpen knives, practice using only knives (wife/GF's kitchen knives
:troll:) that you dont care to screw up; at least until you get the hang of sharpening. Set up your sharpening gear the same way, in the same place every time. Repetition is important to consistent results, as you guys already know. Also, it helps to color the cutting bevel of your knife with a sharpie. This will help you see what metal is and isn't being removed.

If your knife blade is all jacked up, you'll want to start on the course stone. Put sufficient lifting agent (oil) on your stone and spread it around. Place the portion of the blade closest to the handle against the far end of the stone, with the cutting edge facing you. (See photo.)

If your edge is simply dulled and dinged, then the cutting bevel should be flat on each side of the blade. This is good, and means less time/work. If you blade has been subjected to too many quick, field sharpenings without a proper bench sharpening, then the cutting bevels are probably going to be convex, like an axe's cutting edge (unless you've taken the utmost care when field sharpening) and that sucks.

If your bevels are not convex, then you may be able to press the blade against the stone and gently rock the blade back and forth until you feel out the correct angle at which to sharpen the knife. If the cutting bevels ARE convex, then you'll have to reassign the proper angle to each side. I'll come back to this later, but this is where the sharpie trick really comes in handy.

Now make your stroke, trying to run the entire length of the blade (bottom to point) against the stone, before you reach the end of the stone. The longer your sharpening stone is, the fewer strokes you'll have to make. If you watch closely, you will see a small wave in the lifting agent, in front of the part of the blade that is in contact with the stone. You want to keep the blade's point of contact perpendicular to the direction you are dragging it. While doing this, it's crucial to maintain the same angle for the entire length of the stroke. This is the part of sharpening that takes repetition and practice to get the hang of.

As you draw the blade against the stone, you will be tempted to use a second hand to apply pressure to the knife/stone. Don't do it. If you use a second hand, use it only to help steady and mantain the proper sharpening angle and with a VERY light touch. Otherwise the slurry from sharpening will scratch the hell out of your knife's finish.

Now, switch hands and do the exact same thing on the opposite side of the blade. After every 3-4 strokes on each side, wipe the oil off of the blade and examine it closely, making note of the areas that need more attention.

To be continued.
Questions, comments, and pictures of your girlfriend welcome.

 

[Kettenhund]

OK prepare for a potentially stupid question. I worry about being able to maintain a consistent, and correct angle throughout the sharpening process. This is why I thought the Lansky guide type sharpener would be of help. While I'm able to get a nice edge on the cutting edge parallel with where the guide is clamped, I feel it (or I) lack the ability to do the same justice from the radius to the tip. I think the same area may be problematic for me with no guide and a flat stone. The prospect of f*cking up my knives is not sitting very well with me and is causing me a fair amount of angst. Can video be posted here?? I'm one of those guys who learns by watchign and then doing. I can work off an instruction sheet but seeing it done make it a bit easier for me to grasp. Yes, I'm a P.I.T.A. Sorry.

 

[Scholar]

@Kettenhund I really would suggest moving away from a guided system and learning free hand. It takes practice, like everything else in life, but it's worth the time spent to learn how to do it the old fashioned way. My advice on getting the belly of your blade ( the curved portion to the tip) sharp is to start with a cheap easy to sharpen knife (think a Buck Bantam or something similar) and just practice until your body has memorized the mechanics involved with maintaining a similar angle throughout the motion of sharpening. Obviously this is all just my opinion so do what you want, but one day when you're in some third world hell hole and need to put an edge on your pig sticker after using it to open a can of meat, you may thank me

 

[Kettenhund]

Scholar, I get your point, pun intended. Perhaps if I was happy with the edge I got from my Lansky, I would not be paying as much attention to this thread as I am. I dislike the overall job the Lansky does so I really want to get the proper mechanics and tool understood before I screw up my first edge. I'm sure I can find a cheap blade either from a co-worker that had retired one of pick up a Buck at Walmart. I've stropped a blade before but I'm sure that is way more forgiving than a course or medium stone. Once I think I have the technique down, I'kk give it go on my Strider Tanto. I think that would be a pretty easy first test.

Thanks

 

[x SF med]

but one day when you're in some third world hell hole and need to put an edge on your pig sticker after using it to open a can of meat, you may thank me

That's why you always have a p-38 on your dogtags along with your spoon/spork....:wall: ... what you just described is blade abuse. Get one of these, DJ (the designer/maker) had one engraved with an SF crest and my first ODA and sent it to me, it is the best chili devouring implement ever invented and you can have them customized with laser engraving... Cool Groomsman's gifts for a military wedding? I think so.


Now.... a few sharpening tools (generally for the more advanced edge monkey) that would seem very unlikely to have in your kit
1. A jeweler's loupe or magnifying glass (min 8x, I have a 10x - 15x)
2. A good flashlight or light source
3. An assortment of sharpies in red, green and black
4. q-tips
5. pipe cleaners
6. canned air or access to a compressor
7. a bench vise with wood sleeves
8. riffling files
9. bastard files in different sizes, widths, lengths, tooth counts - single cut flats, not double cut.
10. sandpaper/wetsand in varying grades
11. polishing coumpound
12. a torx head driver set
13. jewlers screwdrivers
14. #1, 2, 3 Phillips screwdrivers
15. lithium or dielectric grease
16. a micrometer or two

There are even more esoteric items that'll come into play, but these will allow you to sharpen, tune, clean and inspect fixed and folding knives.

@Barbarian
Have I left out anything major on the list?

 

[Ranger Psych]

OK prepare for a potentially stupid question. I worry about being able to maintain a consistent, and correct angle throughout the sharpening process. This is why I thought the Lansky guide type sharpener would be of help. While I'm able to get a nice edge on the cutting edge parallel with where the guide is clamped, I feel it (or I) lack the ability to do the same justice from the radius to the tip. I think the same area may be problematic for me with no guide and a flat stone. The prospect of f*cking up my knives is not sitting very well with me and is causing me a fair amount of angst. Can video be posted here?? I'm one of those guys who learns by watchign and then doing. I can work off an instruction sheet but seeing it done make it a bit easier for me to grasp. Yes, I'm a P.I.T.A. Sorry.

If it's an edge with a radius, the best technique I found is to adjust the clamping location so that you've got the center point of that edge "up" in the clamp, and you've got as equal as possible edge to the left/right. Then you'll be fine.

Freehanding is great, but there's a reason that pro's use things like the Wicked Edge or other systems. It's guaranteed repeatable with the proper setup.

 

[Barbarian]

@Barbarian
Have I left out anything major on the list?

That's all the important stuff, I think. I might throw in some acetone. It's handy for cleaning stubborn goo.

 

[Scholar]

@x SF med Well I'm not suggesting anyone use their knife for that purpose, but I've done it before in a pinch and I can see it being necessary in a shoddy situation. My point is that if you have the skills to hone an edge free hand, suddenly your options expand 10 fold. The bottom of a coffee mug is a hell of a touch up tool if you can maintain a consistent edge angle.

Also, I'm gonna have to get one of those sporks. They're just badass

 

[x SF med]

Also, I'm gonna have to get one of those sporks. They're just badass

I use mine all the time.... the wife just rolls her eyes, even though she's a vetran too. Tell DJ I sent you, he'll only raise the price a little.

That's all the important stuff, I think. I might throw in some acetone. It's handy for cleaning stubborn goo.

I debated throwing acetone, lacquer thinner and goo gone into the list, but decided against it... mineral oil does a great job for most cleanups, especially if you melt a little green ALO2 8ooo grit polishing compound, always have some handy for the bench strop, and those nasty stains on blades it makes the blades so shiny.

Besides, what acetone can do to micarta, or bone or leather or rubberized handle material is not a pretty sight at all. Which reminds me, 000 piano wire (high E, for the musically inclined; .0125mm for the engineering types) is great for getting under glued down/gunked down handle materials... make sure you tie wooden handles on the ends, and wear welding or ranching heavy leather gloves - you are basically creating a wire knife/garrotte to get under the material and cut the glue, it will slice right through flesh.

I know what I forgot! a good supply of microfiber, cotton terry, and well washed diapers for rags... well washed diapers are a godsend for the areas that require hand polishing, the others are to clean up messes and protect your working area.

If you buy a good stone - buy or make an equally good stand, with grippy feet, a solid sharpening surface is a must. If you use a Japanese water stone, the rubber mat/netting you use to keep carpets from slipping is great, or a placemat made of similar material, they do not work so well for oil/detergent based lifting agents.

Bill Harsey sometimes uses Simple Green as a lifting agent on his Norton manufactured stones, I've tried it, it works great - but mineral oil is cheaper, so I use it most of the time.

I think the next topics - not tonight - should be prepping and care of sharpening stones, and the debates for and against manufactured and natural stones (remember the Japanese have been manufacturing stones for hundreds of years).

Think about the pros and cons of both types of stones, and diamond, carbide or ceramic sharpeners.

 

[compforce]

If you buy a good stone - buy or make an equally good stand, with grippy feet, a solid sharpening surface is a must. If you use a Japanese water stone, the rubber mat/netting you use to keep carpets from slipping is great, or a placemat made of similar material, they do not work so well for oil/detergent based lifting agents.

Drawer liner is the bomb for this. I have a stand, but Drawer Liner - Grip-it 5 Foot which is in your local grocery store is cheap and works regardless of lifting agent. I also use it under my cutting boards.

 

[x SF med]

Ok... a board member needed to borrow some fixed blade sharp pointies for a deployment E&E kit... a few minor requirements were one had to be stout enough for batoning/chopping/heavy cutting but not so big that it could not be concealed/in a small E&E bag, one had to be carryable without being obtrusive, one had to be for last ditch me or the other guy situations... My discretion for the actual knives (this person would have gotten my Chris Reeve GB 7" if it fit the bill, or one of my irreplaceable daggers had they fit the bill)

My choices from my collection were:

1. Bussee Scrap Yard 5" for the batonable/heavy chopper (Not a fan of the maker, but the scrapyard is a solid little packable camp knife)
2. Concealable EDC - a Buck skeleton Skinner from RMEF - great on the belt fixed blade, has a shackle key, and a scalable hex/gas bottle wrench. drawback is that it is a bear and 3/4 to sharpen because it is a double recurve edge shape
3. Me or him knife.... a first production run cold Steel- Kobun wakashabi tanto...(told you this person rated, I got this knife from the founder of BladeTech because he wanted beer money for the evening and his wife told him to downsize his collection)

I spent most of a day inspecting, and resharpening all 3 0f them, right down to polishing the edges on the bench strop. I Also let this member know that he has to come visit for knife sharpening lessons, because he only uses diamond hones.... I own 3, I use them for re-cutting blade profiles when people do stupid human tricks with their knives and break the tips off, they're as bad as most electric knife sharpeners or the carbide pocket sharpeners (ever noticed the shavings coming off the blade? they is chunks o' yo knife...) But my diamond hones are a DMT blue/red, a CRKT pocket wedge, and an EZ-Lap 8" - the CRKT and EZ-Lap are diamond impregnated D2 Tool steel with channels cut in them... in some cases, they are faster than using a grinder to re-cut.... I don't know why people use diamond to sharpen for everyday use... it leaves a very rough cutting edge.

So, I've been practicing myself.... and it hit me, the hardest part about writing this thread, is going back to the learning stage... forgetting what I know, to make it easy for all of you... I can't erase the muscle memory for freehanding angles, forget the sounds of an edge cutting properly, not see the way the lifting agent polls, follows the edges and covers the edges in the different stages of sharpening - but I can pay attention to them and figure out ways to explain them. This is part of the slowdown in getting stuff up here... and I need a filming/photo assistant who will focus on the knife/stone/angle without getting my ugly mug into it...

I'm working on getting more detailed info up... please be patient...

Everybody go out and buy good sharpening gear and cheap knives to practice with.... poor quality stones = bad edges.

 

[x SF med]

I've stropped a blade before but I'm sure that is way more forgiving than a course or medium stone.

Just caught this on my umpteenth time re-reading the thread, and it brings up some Do's and Dont's, suggestions and Admonitions...

1. Just because you have a coarse stone (grit #<400), or a medium (grit #<600) does not mean you have to use it every time you sharpen.. Coarse is for really evilly abused, bar stock level edges, it rips LOTS of steel off your knife. Medium is for butterknife level edges, still takes off a lot of steel, but you don't end up with a pile of metal shavings in your lifting medium.
2. Inspect the edge before you even think about what stone to use, inspect means a light test (hold the knife edge up, point toward a light source and look down the cutting edge from the handle, any shiny spots are flat spots in your edge). Use a magnifier to look at the edge profile(s) - minimum 8 power magnifying glass, I use 10x and 15x jeweler's loupes -you can actually see the matrix shifts in the steel, temper changes if the blade has been heated/cooled excessively and stress areas as well as the edge itself.
3. Do not drink and sharpen, you get a shitty edge at best, end up in the hospital at worst.
4. Don't get discouraged - it took me a couple of years of consistent practice under the guidance of some stellar knife makers to even get passable at putting a consistent edge on a knife. Yes, years.... sorry, it really does take time to get this down.
5. Don't skimp on your equipment, but don't over buy ... collect the gear as you need/use it... 20, 25, 50, 75, 5 bucks occasionally does not hurt like doing it all at once and saying to yourself .... "Self, this shit is too expensive to use, I just dropped $600 on rocks and crap.... am I an idiot?" instead of going back later and saying, "holy crap, self, I have a bunch of money tied up in this, I'm glad I enjoy it and my knives are the envy of my friends because they always cut and don't have scratches all over them from sharpening on a coarse stone."
6. Practice
7. Practice
8. relax
9. use a knife you think you sharpened well
10. be proud of your efforts and time spent

 

[SpitfireV]

Thank you guys for all your efforts in this thread.

I have a question though but it's a bit outside the remit of the thread. It's about using a strop to sharpen a razor. I'm looking at buying a straight razor soon and I'd like to be able to sharpen it properly before I use it.

 

[x SF med]

Thank you guys for all your efforts in this thread.

I have a question though but it's a bit outside the remit of the thread. It's about using a strop to sharpen a razor. I'm looking at buying a straight razor soon and I'd like to be able to sharpen it properly before I use it.

Soften the strop, use the natural sag in the strop, lay the razor on the strop spine slightly tilted up away from the leather (~1cm ish), pull the spine towards you first then flip the razor and push the spine away from you.

If you have any doubts, find an old school barber and ask for help.

 

[SpitfireV]

Great, thank you very much.