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Knife sharpening

11 May 2013
@ 04:40 pm (GMT)

Richard Butler

http://www.knivesshipfree.com/pages.php?pID=4&CDpath=0
This link is for a great knife sharpening video. It is for convex edges but seems to apply to straight edges as well. The leather strops polish the blade and assist in making them very sharp. I sharpen my Svord knife using this method, admittedly after straightening the edge a bit on a stone.

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12 May 2013 @ 06:59 pm (GMT)	Quote this Nathan Foster Re: Knife sharpening Hi Richard- good to have this sort of thing to view thanks. One of other site members (Warrick) is a knife maker, extremely dedicated, lover of metallurgy, he has urged me to make a strop for a particular knife. I am still looking for a local source, for a strip of bull/cow hide. Just a heads up Richard, Reloaders will soon have the 168gr 7mm Matrix in stock if you ever feel the need to change bullets in your RM. Warrick, could you have a look at the vid when you get a chance please.
12 May 2013 @ 07:13 pm (GMT)	Quote this Nathan Foster Re: Knife sharpening For NZ readers, the 'soaps' are available from PPS in Hamiltion. A80 is the black bar, commonly called carburex, it runs from about 900 to 1200 grit (but can be considered very course if used on high speed sizals as opposed to the strop). The green ali oxide bar is also available from PPS, normally used for polishing brass and ali. Hifin (white) and Lee (yellow) are also fine grit bars, up around 2000 grit.
12 May 2013 @ 08:21 pm (GMT)	Quote this Warrick Edmonds Re: Knife sharpening It's a great set of short vids, the presenter is clear and communicates really well. I suppose there are a couple comments he could have included, mainly why you might want a convex edge and which knives benefit from it. (Its often called a grape-seed edge in the knife world). The convex edge gained popularity with the advent of competitave cutting events in the US. Prior to that most knives were all about hollow grinds and fine bevels. These competition knives are typically bowie / large camp / chopper styles, around 8 inches and rank as heavy metal. The comps require the knives to chop through a 4 x 2 of pine, ropes, ping-pong balls and other events, then shave hair at the end. Nearly all the competitors use convex edges because compared to a bevel grind, a large thickness of steel is carried closer to the edge, providing strength and avoiding chipping when whacking thick wood. During these comps the knives are assessed for chipping and other failures, which would be a black mark against good steel forging. A thicker edge also allows the knife steel to be heat treated harder as brittleness is less of an issue. Now it comes down to personal taste, in the field I pref a fine, very sharp blade and spend hours farting around like a surgeon, so use a bevel grind. I happen to know Nathan prefs a heavier knife and does things quickly and efficiently, so he might consider the convex edge. Either way, the loaded leather strop for shed and field is a great idea and I've been using one for the last decade, if works for both styles of edge. If using a bevel edge on a strop make sure the angle of edge to leather is significantly less than the angle you used on the stone or you will round off all your hard work as the spongey material springs up behind the dragging edge. convex edges are not appropriate for hollow ground knives, which are all about super fine, razor like profiles, and should not be used to cut down trees. If you use a leather strop regularly you will find that you can go months without re-sharpening. Sorry the reply is a bit wonky, I've got a broken hand and typing is a pain. Warrick
12 May 2013 @ 08:56 pm (GMT)	Quote this Nathan Foster Re: Knife sharpening Thanks Warrick, that was fantastic, really appreciate it.
14 May 2013 @ 10:50 pm (GMT)	Quote this Martin Taylor Re: Knife sharpening Thanks Guys, Some really great info contained in those vids, Cheers Marty
20 Dec 2013 @ 02:39 am (GMT)	Quote this Bob Mavin Re: Knife sharpening Heads up guys!!! For many years I've been using my Dad's piece of, looks like seat belt material with a hook on one end, rub some cutting compound on it, fits easily into a pack & works better than a steel. Cheers Bob
17 Nov 2016 @ 07:48 am (GMT)	Quote this Andrew Murray Re: Knife sharpening Found this old thread, the link is dead though. I've got quite a bit of experience in sharpening (as a straight shaver and knife user in general). From a razor perspective (for straight shaving) having a progression of stones for sharpening is crucial. I usually finish on a natural Thuringian stone which is hard to measure grit size (because it's a natural stone) but is probably the equivalent of around 14k-15k grit. Warrick you may know the brand, it's an Escher, I inherited it, the lucky soul I am. I start at 1k for my razors on a ceramic Suehiro 1k/3k combination stone (SKG-27 Toishi). It's fantastic. But 1k is somewhat fine for heavy bevel work as may be required on knives. As the razor gets more polished I decrease the grit size for a finer finish until it is literally razor sharp. There are 2 types of bevels I am aware of, a European style and a Japanese style. The main difference in simplistic terms is that the Japanese style tends to be a single angle bevel all the way down at roughly 25-30 degrees (12-15 degrees each side). Japanese sashimi knives have a single bevel and a flat side for ultra fine cutting and sharpness, as is required for sashimi. The European style bevel is shorter and more stout an angle roughly 40 degrees (20 degrees each side). I think this maybe be what you're referring to as convex blades if I'm reading right... Either way, the steep the angle, the sharper the knife but the quicker it dulls. A Euro style bevel is preferable for heavy work as Warrick mentioned. I prefer a sharper edge on my kitchen knives, so I prefer to sharpen as demonstrated in the video below. It's by Global brand knives but I'm not in anyway promoting their brand, it's just a good demonstration of how the Japanese will sharpen their knives. Not that I've used the guide rail but I'm sure it's a good idea. https://www.youtube.com/watch?v=te1KIpGyz-4 If you ever get the chance I'd highly recommend researching how the Japanese make Katanas and other swords. Absolutely fascinating. Here is a National Geographic video: https://www.youtube.com/watch?v=VE_4zHNcieM
17 Nov 2016 @ 08:13 am (GMT)	Quote this Andrew Murray Re: Knife sharpening Here's an example of a Hollow Grind (Bellied hollow grind) You can see the belly of the razor right near the bevel. This is known as a singing razor as it makes a "shiiing" kind of noise when your strop it. Speaking of strops, I'd be curious to known how effective they are on hunting knives with wide bevels. In my understanding stropping a hunting knife would be superfluous unless you've sharpened up to around 15k. Which seems overkill for a knife and would be incredibly time consuming on a particularly hard edged blade. The angle at which you'd also need to hold it would be quite steep and hard to maintain through out a stropping session. Again, with razors, you hold the bevel and the spine flat on the strop (and also when on the stones), so maintaining the angle isn't really a challenge. The challenge is the correct pressure you strop the razor with (very light).
19 Nov 2016 @ 06:35 pm (GMT)	Quote this Warrick Edmunds Re: Knife sharpening Hi Andrew. Just to clarify, when I was talking about a convex grinds I was describing the actual cutting edge as apposed to the bevels, the thinnest and last few millimetres of the blade. Just so we’re both on the same page, the bevels are the large, flat/convex/whatever shape plunging from the knife spine to the cutting edge. Once down at the thin bits on a hunting knife there are usually two more very fine changes of angle leading to the cutting edge. The first is a primary, which changes angle from the bevel toward a finer edge and then there’s the smallest of all called the secondary, which is a very fine change of angle toward the actual cutting edge. Typically the secondary is what you hone, so it will progressively wear back toward the primary. When it gets close to the start of the primary it’s time to re-sharpen. Now this may be different to a razor, you’re the expert there. Nearly all primaries and secondaries are flat grinds because they’re done using flat stones, the flat surfaces of wheels, etc. They can become quite sharp however their Achilles heel is that in use the very fine cutting edge may roll over, forming an almost invisible wire that runs the length of the blade. Most of the time this is what makes a knife seem blunt. Stropping will take off this wire and give you back your hair splitting edge. Some hard users like to have what’s called a grape-seed edge, because it supports the actual cutting bit with a lot more metal and is therefore longer lasting. Not many folk end up with a grape-seed edge because it’s quite hard to make and requires a lot of practice. Yes, there are different grinds for the bevels but they can be broken down into three groups. Firstly there’s the convex bevels on both sides that is demonstrated with your razor photo. Secondly there’s a flat grind, which means that the bevels on both sides plunge at the same angle from the spine to the primary cutting edge. Thirdly there’s the chisel grind, which has one flat side and one bevelled side. The chisel grind is not that simple in practice though because the better knife makers also put in a finely tuned convex grind on the inside bottom couple of centimeters of the flat side, especially on high-end culinary knives. These make the sharpest knives and are the easiest to maintain at peak sharpness of any type. They are very hard to get right because heat treating will often result in warps bends and fails of thin metal so most of the fine grinding is done afterwards, which takes a lot of time and patience because you have to keep it cool so as to not wreck the tempering. yours Warrick Edmonds
19 Nov 2016 @ 09:01 pm (GMT)	Quote this Andrew Murray Re: Knife sharpening Thanks Warrick, I appreciate the clarification. Can you also define the strop you use? Is it similar to the one I use for my razors? A length of leather? Or felt/canvas with some polish compound like diamond paste or Chromium Oxide? Or is it the steel sticks? I'm struggling to see how leather would help at a thicker edge like a knife compared to a razor, I imagine it's too soft, and the angle at which you would strop the knife, which sounds a little more confusing for a convex edge too, as the angle would be changing right up until the very edge, do you roll the angle as you strop? With flat grinds, I appreciate the effort that would require to sharpen on a knife. I use a layer or two (depending on the blade) of electrical tape to help lift the spine off the stones, which helps me not to hone the spine, this extends the life of the blade considerably.
20 Nov 2016 @ 12:13 am (GMT)	Quote this Warrick Edmonds Re: Knife sharpening Andrew Just to confuse matters I used the word convex in the last parra twice when I should have said convex, sorry. Grape seed edges are convex, chisel grinds have a slight concave on the bottom of the flat side, hollow grinds have convex bevels each side like your razor. yes, the strop I use is a piece of wood with thick bovine leather glued to it so that the smooth side is out, load it up with fine cutting compound. Honing is different from sharpening. Honing is usually the removal of a fine wire that blocks the cutting edge, this is easily done on a strop or steel before each use of the knife. If using a strop, make sure the angle you have between blade and leather is significantly less than you have when sharpening. Leather will roll up around the edge and round it off so you need to compensate for that. If you're using a steel then this isn't a problem. Sharpening is only done every now and then. This is when you've exhausted the ability to hone successfully and you need to put on a new primary cutting edge. Sharpening removes a lot of metal compared to honing and if you sharpen all the time you'll wear out your knife relatively quickly. What will happen is that as you take metal away, you'll push the cutting edge further and further up into the thicker metal of the bevels. All this works very well on a hunting knife, especially skinners and also culinary knives. I do this in the field when I hunt and also in my workshop when knife making.
20 Nov 2016 @ 12:18 am (GMT)	Quote this Warrick Edmonds Re: Knife sharpening Andrew Just to confuse matters I used the word concave in the last parra twice when I should have said convex, sorry. Grape seed edges are convex, chisel grinds have a slight concave on the bottom of the flat side, hollow grinds have concave bevels each side like your razor. yes, the strop I use is a piece of wood with thick bovine leather glued to it so that the smooth side is out, load it up with fine cutting compound. Honing is different from sharpening. Honing is usually the removal of a fine wire that blocks the cutting edge, this is easily done on a strop or steel before each use of the knife. If using a strop, make sure the angle you have between blade and leather is significantly less than you have when sharpening. Leather will roll up around the edge and round it off so you need to compensate for that. If you're using a steel then this isn't a problem. Sharpening is only done every now and then. This is when you've exhausted the ability to hone successfully and you need to put on a new primary cutting edge. Sharpening removes a lot of metal compared to honing and if you sharpen all the time you'll wear out your knife relatively quickly. What will happen is that as you take metal away, you'll push the cutting edge further and further up into the thicker metal of the bevels. All this works very well on a hunting knife, especially skinners and also culinary knives. I do this in the field when I hunt and also in my workshop when knife making.
20 Nov 2016 @ 12:54 am (GMT)	Quote this Andrew Murray Re: Knife sharpening Thank you again :) I'm getting a much better understanding with the definitions being explained for me. I had a look at your site too Warrick, very nice work. When sharpening what grit level do you start at? 600ish? I have quite a few knives at home in need of some attention and would very much love a lower grit stone. I found an old Naniwa 1k/3k combination stone and even at the 1k level the cutting is very slow... What level do you go to on the higher end as well? I find that for my needs (all kitchen knives), going beyond 1k is a bit excessive, except for the fish filleter, which is nicer at around 3k. I have also sharpened the top side of the point of that knife to create a double edged blade for about 5mm, I find it helps sometimes around the head.
20 Nov 2016 @ 11:26 pm (GMT)	Quote this Warrick Edmonds Re: Knife sharpening Andrew If I'm putting on an edge for the first time, I use something like 120 grit, but that's removing a lot of metal. If you don't have a coarse stone, try using a sheet of wet and dry sandpaper taped to a flat surface. You can revert to stones once you've gone down the grits somewhat. Being a knife maker, I use my belt grinder to do this initial setting of the edge. It's actually a skilled job and you wouldn't attempt it without guidance cause it's dangerous. However there are other ways. If you have a bench grinder I strongly recommend you invest in a set of paper wheels. Go to the Gameco website and look up the Razor Sharp sharpening wheels. These are the bees knees and I use them all the time for general sharpening and you will end up with a polished edge. You'll never use a stone again other than in the field.
21 Nov 2016 @ 08:09 pm (GMT)	Quote this Andrew Murray Re: Knife sharpening Does the steel get hot? Does it affect the tempering? I have learned, quite dangerously early on that power equipment and blades aren't a good mix... But it was a bench grinder with a pretty low grit wheel at very high speed. Plus it was a hollow ground razor, very thin steel. Did you end up getting the second email I sent through, I got a couple of bounce backs...
21 Nov 2016 @ 09:10 pm (GMT)	Quote this Warrick Edmonds Re: Knife sharpening Yes, you have to be very careful about machines and knives. However the paper wheels are relatively easy to use, I think the seller has a video you can watch shows how they are set up, which is with the spin = down and the cutting edge = down, so there's nothing pointy facing the user. (BTW, I've got zero financial interest there, I just think it's a good product) Patience is the key. A lot of knife makers use bare hands when putting their blades onto the belts so that they can control the temperature. Essentially if it's too hot to hold then you might be affecting the temper etc. I don't. I always wear thick leather gloves. In fact I tape strips of thick sheath leather around some of the fingers for extra protection. I don't want to be less a digit or two. So it's a matter of many quick touches, wait a whiles and repeats. Yes, I imagine a very thin razor would present its own set of challenges re heat treating, however the principles are similar to the finely ground cooks and skinning knives I make, so I can see where you're coming from.
22 Dec 2016 @ 12:42 am (GMT)	Quote this Ryan Nafe Re: Knife sharpening If anyone is interested in learning a HUGE variety of things about knives and sharpening, I would encourage you to check out this link: http://www.cliffstamp.com/knives/ Cliff is not someone who knowingly makes unsupported claims, the link above is a genuine source of knowledge. I haven't seen anyone who is as rigorous during testing of knives and stones as him, he literally does double blind studies and will do many runs of the same test for an increase in sample size for the experiment. He also tends to be extremely responsive to questions.
06 Mar 2017 @ 02:58 pm (GMT)	Quote this Kai Larson Re: Knife sharpening This is the best knife sharpening tool I've ever used. Obviously not for use in the field, but for sharpening at home, it can't be beat. I use it for everything from my kitchen knives to hunting knives, to survival knives. No idea if it's available in New Zealand or not. http://www.worksharptools.com/ken-onion-edition-knife-and-tool-sharpener.html
26 Oct 2017 @ 03:58 am (GMT)	Quote this Joshua Mayfield Re: Knife sharpening Last year this thread prompted me to read up on one of my state's unique natural resources - novaculite. Arkansas whetstones are pretty widely known, but it dawned on me that I didn't actually know much about them. In my reading I saw that two of the leading suppliers of finished stones are located just minutes down the road from a place my wife and I take the kids two or three times a year. So I called them up and asked if I could drop by. At both places real, live, knowledgeable people answered the phone. One is set up for internet sales only and their insurance won't allow onsite visitors or customers. The other said come on by. So I paid the folks at Dan's Whetstone a visit and I was treated far better than I deserve. Dan Kirschman, the founder, spent about an hour and half showing me around and educating me on novaculite. It was fascinating. These folks find and remove the rock from the ground themselves and carry the process through to a finished, marketable product. They've engineered and constructed some of their equipment themselves and acquired some equipment from all over the world. Dan was particularly proud of a huge old saw he bought from an Italian marble company years ago that allows them to cut larger pieces of novaculite into finished stones than just about anyone else, when they find pieces of large uncracked and unblemished raw stone. Anyhow, I could ramble on even longer than I have. I really enjoy finding a family-founded, expertly run business like this and feel grateful for their hospitality. I'll do business with them for a long time. https://www.danswhetstone.com/
26 Oct 2017 @ 09:08 am (GMT)	Quote this Andrew Murray Re: Knife sharpening That's awesome Josh. I do love sharpening. The bench grinder has since gone and I am still looking for a lower grit stone for my knives. I recently purchased a hunting knife (cheap one) and the blade needed a lot of attention. It took a very long time to get the bevel and edge right.
03 Mar 2018 @ 05:49 pm (GMT)	Quote this Warwick Marflitt Re: Knife sharpening Check out this handy tool. https://www.youtube.com/watch?v=k3SbEWFSA8s
06 May 2018 @ 09:10 pm (GMT)	Quote this Andrew Murray Re: Knife sharpening I have finally bought the bullet and purchased a low grit sharpening plate, a diamond one. Combo 400/800. I have stainless knives for the kitchen and hunting and they take forever on my stones. They were bought for my razors so they are high quality and the lowest is 1000grit. It just takes too long to do heavy bevel work on the knives. And some of my knives still need heavy bevel work.
07 May 2018 @ 11:30 am (GMT)	Quote this Warrick Edmonds Re: Knife sharpening Now that you've all got your knife sharpening kit, here's a thought on how to use it. There's a mob in Sydney who have been applying considerable time and science over the last few years to understanding what makes a sharp edge. It's their professional business, so they're looking for a point of difference. But that being said, they've been good enough to publish some of their results on Australian Blade Forums. Boiling it all down to the important result, they've concluded that the best angle is 15 degrees per side. Doesn't matter if the knife is thick or thin, this angle remains the one to go for. The more precision you apply to replicating that angle from side to side the sharper your end result will be. I've adopted this angle in my own sharpening and have noticed a difference. If you can afford it or have the skills to make one, you might like to arrange a mechanical device that can help you keep 15 degrees. yours Warrick Edmonds Riflebirdknives.com
07 May 2018 @ 12:12 pm (GMT)	Quote this Andrew Murray Re: Knife sharpening Hi Warrick, Cheers for the info. That's really cool to know. I take it that they are using a flat or scandi grind or sabre type grind. I don't imagine a convex grind can really be measured by angles. I assume that it is 15° for each side totalling 30° or is it 15 in total?
07 May 2018 @ 12:15 pm (GMT)	Quote this Andrew Murray Re: Knife sharpening Perhaps if I read more thoroughly before posting I can answer my own questions.