Good way to sharpen knives? - Page 1
Forum section: electronics / general

author: Ampera
author_rank: Super Contributor
timestamp: February 07, 2017, 06:39:51 am
content: Yea, yea. I know this isn't EE, but I don't have a knife forum I can visit, and there are enough people here, someone's bound to know something.Anyways, I have knives. They are dull. They aren't large either. I have an electric sharpener I had gotten at some point, which is probably alright for kitchen knives, but for small like swiss army knives, they are rubbish. So I was wondering, what do I do?I understand enough to know there are polishing stones for knives, they aren't damaged or anything, they just need a bit of a sharpening up.tl;dr, where do I begin?

author: Vgkid
author_rank: Super Contributor
timestamp: February 07, 2017, 06:44:58 am
content: I have one of these 5 stone Lansky sharpeners. I use 20Deg for the kitchen knives, 25 for everything else. It is fun to put a 17Deg angle on the kitchen knives.Best way to learn it is to just do a lot of experimenting. I used it a lot when I was in the scouts.

author: amirm
author_rank: Regular Contributor
timestamp: February 07, 2017, 06:50:20 am
content: There are three types of stones: oil, water and diamond. I prefer to not mess with oil and when I can, try to use diamond. Here is a good demo of sharpening pocket knives using diamond (at around 3:00):

author: Vgkid
author_rank: Super Contributor
timestamp: February 07, 2017, 07:12:38 am
content: Those diamond stones are nice. They are a bit cheaper now, then when I bought my oil stones.

author: Assafl
author_rank: Frequent Contributor
timestamp: February 07, 2017, 07:34:55 am
content: In a nut shell, there are two stages to sharpening:1: creating the edge2: honingYou create and edge with a low grit stone (I have stones from 100 grit to 1000 grit for this).You hone with >2000 grit stones. Or - with a hone; or - with a strap (with chromium oxide - like in the old movies); or - with a newspaper (yup).A few pointers - in new to sharpening the lowest grit that that ever touch you knife is 1000 grit. An "Arato" (Coarse) 180-600 grit stone will destroy your knife in two strokes if you don't keep the knife at the correct angle steadily. (To keep the angle steady there are excellent systems out there like the Apex Pro from edge pro; I use it when I am rebuilding the dual beveled edges to hard wearing or abused kniveshttp://www.edgeproinc.com/Apex-Model-Edge-Pro-System-c3/). I have had zero success with clip on angle bevels, etc.There are Waterstones (lubricated with water) and there are oil based stones and there are diamond stones. They are equivalent, and I used all three, but Japanese Waterstones are always my favorite (and a folding DMT dual grit diamond stone are my favorite for camping and outdoors stuff). Of the Waterstones, I really like Shapton Ceramic Whetstones and have 180, 400 and 1000 Arato stones, 5000 & 8000 "Shaigeto" very fine honing stones. I also have a 12,000 grit I only ever use to make a mirror finish and is a real pain to use and is not really recommended for anything other than carving.Regarding grit: Depends on usage. For kitchen use I'd recommend a 1000 and perhaps a 2000 grit stone for beginners - 5000 is a bit high but I work fast, am experienced and like it. For a Luthier (or other wood carver), probably 8,000 grit or more. Some delicate carvers like to go up to 16,000 grit and higher. For shaving - chromium oxide on horse leather strop is best - usually 0.5uM correlates to I think 30,000 grit - but will slice you open like a Pez dispenser if you are not careful.Remember to dunk the stones in water/oil depending on the type of stones. Never dunk a Norton oil stone in water or a water stone in oil. I have a Naniwa "bridge"https://www.sharpeningsupplies.com/Naniwa-Sink-Bridge-P293.aspxthat lays across the sink so I can have water flow during the sharpening routine. Makes cleaning easy....One of the important tasks of knife sharpening is getting a feel for the blade. How do you know you are sharpening? Murray Carter trusts his fingertips. If you lay 3 fingers on a blade - if it is sharp - they will tell you "HELP - please don't slide me on the blade - I am terrified" much more than for a blunt knife. There is the back of a fingernail test (a sharp knife will not slide at most angles); removing arm hair (works until no longer hirsute); "plucking" the blade; cutting paper (awful - you just blunted the good work); Murray carters "lube free shaving" - ouch.Holding a knife for sharpening: The important tips here are to hold it steady (usually by the handle) with a bit of twist (to force the cutting blade to the stone). Lay 3 fingers on the blade (be careful) and exert light pressure. Slide the blade along the entire long surface of the stone. repeat 5 times. Move the 3 finger to the next spot along the blade and repeat. One hand controls the angle, the other controls the pressure. For honing the lightest pressure possible is best. Try it on a newspaper - you'd be impressed.Last point about sharpening - it is Zen. If your knives are good (and as you'll become a better sharpener - your knives will become better) you'll end up cutting yourself (sorry!). That will happen when you lose focus. Sort of like the Japanese martial arts films when the old master gets the student whenever they lose focus. Over time, like a good knifesmith, Pavlovian conditioning will have you tune out sounds, tune out the children and wife and have 30 minutes of pure focus bliss - once every fortnight or so. Bliss.Murray Carter has a youtube playlist for sharpening knives:https://www.youtube.com/playlist?list=PL9E3C18FBC2002035

author: mmagin
author_rank: Frequent Contributor
timestamp: February 07, 2017, 10:03:03 pm
content: I always hated sharpening until I started doing this with cheap diamond hones:https://paulsellers.com/2014/11/more-sharpening-knife-notes/

author: Cubdriver
author_rank: Unknown
timestamp: February 07, 2017, 10:29:03 pm
content: I have the Lansky set, too, and am happy with the results.-Pat

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: February 07, 2017, 10:32:49 pm
content: Japanese whetstone.

author: Gregg
author_rank: Super Contributor
timestamp: February 07, 2017, 11:08:40 pm
content: Try the Wicked Edge forum:http://knife.wickededgeusa.com/for a lot of insight even if you don't own or want to pay the price of a Wicked edge sharpening system. The forum is full of good comments without much infighting or trolling.

author: Assafl
author_rank: Frequent Contributor
timestamp: February 08, 2017, 10:50:56 am
content: Quote from: mmagin on February 07, 2017, 10:03:03 pmNice way to position the knife at a particular angle. It is what the Apex Pro does (but the Apex pro is adjustable - and also holds the abrasive - the negative side is that it is expensive).BTW - a good way to figure out the angle of the bevel is to mark the edge bevel with a sharpie. Then - pass the knife over the abrasive once - If you are the proper angle - all of the sharpie will be erased - evenly. If you are at a different angle - only a part of the marking will be removed (too steep - the sharpie will be exposed at the blade end; too flat - only the area close to the second bevel will be exposed).

author: JPortici
author_rank: Super Contributor
timestamp: February 08, 2017, 10:54:33 am
content: Quote from: TwoOfFive on February 07, 2017, 06:39:51 amyou don't have the old man in an apecar and megaphone that goes around your block at 7 am to announce his presence and his most needed services?huh, it must be an italian thingDonne, è arrivato l'arrotino!Gals, the blade-sharpner is here!

author: GreyWoolfe
author_rank: Unknown
timestamp: February 08, 2017, 05:34:45 pm
content: I have this Spyderco sharpner:https://www.walmart.com/ip/17687555?wmlspartner=wmtlabs&adid=22222222222014444057&wmlspartner=wmtlabs&wl0=e&wl1=o&wl2=c&wl3=10363682990&wl4=kwd-1103065135107&wl12=17687555_10000001278&wl14=spyderco%20sharpner&veh=sem

author: Assafl
author_rank: Frequent Contributor
timestamp: February 09, 2017, 08:21:09 am
content: Quote from: JPortici on February 08, 2017, 10:54:33 amOh wow - had to look this up and found this:We have one on a Vespa doing the same. But he visits restaurants and meat packers only.Does a Vespa qualify as sufficiently Italian?

author: babysitter
author_rank: Frequent Contributor
timestamp: February 09, 2017, 09:22:04 am
content: Take it to the shower, sweep it over the tiles gently.(Says a guy who polished stuff including optical fiber on an aluminium door using the hard anodisation as polishing material.)

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 10, 2017, 12:41:48 am
content: The stones are less important than the practice. Some folks even swear by emery paper on plate glass. I would recommend learning on less than your best knives, because you might well ruin a couple as you learn. Xacto knives are an interesting choice, dirt cheap so you don't mind mistakes, but good enough steel that you actually can maintain an edge on them. The basic ones also have a straight edge which greatly simplifies the process.Which leads to guides. I have never had any luck using a guide when sharpening a blade that has curvature to the edge. (Like almost all pocketknife blades, except for some sheepsfoot blades.) The geometry has to change to follow the curve and I am not aware of any guide that does this. So at most, use a guide a few times to get a feel for the angle and then go with out.The standard Victorinix knives are not that good a steel, and are actually more difficult to sharpen well than better knives. Don't be discouraged if your initial results aren't terrific.

author: mmagin
author_rank: Frequent Contributor
timestamp: February 10, 2017, 01:47:06 am
content: Carbon steel is vastly more enjoyable to sharpen than most stainless tool steels. This is why I love the cheap Opinel Carbon pocketknives even if they need some care to prevent corrosion.

author: Vgkid
author_rank: Super Contributor
timestamp: February 10, 2017, 07:03:23 am
content: Quote from: mmagin on February 10, 2017, 01:47:06 amThose are some nice looking knives.

author: Assafl
author_rank: Frequent Contributor
timestamp: February 10, 2017, 07:20:49 am
content: Quote from: mmagin on February 10, 2017, 01:47:06 amIt is easy to make hard steel or ceramics - that maintains an edge for long but is really tough to sharpen.It is easy to make soft steel that doesn't maintain an edge but is easy to sharpen.The trick lies in making steel that is at-once hard and easy to sharpen.To your point, I'd sayforged knivesof a given hardness sharpen easier than stamped ones (carbon steel is usually forged and repeatedly hammered with a pneumatic hammer). The reason being that the hammering "breaks" the steel crystals and thus enables one to have both high hardness of the individual crystals (high 50's to mid 60's Rockwell) while making it easy to sharpen (basically "pulling" chunks of steel out).Yes - my favorite "throwaway" knife is a Higonokami which uses "Blue Paper" Steel (Ao-Ko) and costs less than 20$.