Please Note: The following are personal techniques and should be used with caution. The KnifeCenter does not endorse any of these methods in particular and presents them here for educational purposes only. Use them at your own risk.
I have been reading your webpage on sharpening with some interest.
I am a chartered mechanical engineer and think that it is appropriate to add a few comments. Grinding is common in industry and the science of removing metal is well understood. The process of removing metal to sharpen a blade is a grinding process. Grinding works in the same way as cutting (on a machine lathe or even using a drill bit) that is to say that the metal is removed by placing a small layer of the metal under shear. The scale of removing metal by grinding is much smaller than turning but the physics is the same. (Some might argue that you hone or lap a blade but the difference again is only of scale - the process is still the same i.e. removing a thin layer layer of metal under shear).
Anyway, I was interested in the comments regarding lubrication. I am not an expert on sharpening and won't argue with the art of sharpening - as with all engineering the proof of the pudding is in the eating, however I think you should understand the role of lubricants in grinding.
An industrial grinding process would always include lubrication for two reasons. Lubrication removes the waste metal so that the edge of the cutting or grinding compound (not the edge of the blade) is kept clear and efficient. Secondly the lubricant cools the edge where the the cutting is taking place. This prolongs the life of the cutting tool (grinding stone etc) and maintains the mechanical properties of the steel being sharpened ie stops the metal from being annealed or aged.
The Following Sharpening Tips are Personal Opinions Furnished by another Individual
After looking over your knife sharpening tips I thought that I'd pass on mine. If I'm away from home I carry a large double faced wet stone with me. I don't use oil to sharpen with. It tends to do two things. It lets the collapsed cutting particles clog the surface of the stone and it also lubricates the surface so that the metal of the blade gets cut much more slowly. If you are in a hurry to bring up the edge of a knife then a stone with a clogged or slippery surface is counter productive. I use water on the surface plus a few drops of liquid dishwashing detergent. It gives the right ammount of slip plus prevents the surface from clogging. The last thing I do is dry the knife and lube it and flood the stone, wash it, and dry it.
If I'm at home I use an electric grinder which I have adapted. The adaptation consists of turning the grinder around so that I'm facing the back side. I've replaced the stones with a rubber bonded wheel and a sewn canvas wheel. The reason for turning the grinder around is because you want to sharpen the knife on the top with the wheel travelling "AWAY" from you. You also need to sharpen with the blade pointing away from you. If you sharpen an edge on a grinding wheel you always sharpen into the edge. If you did that with a rubber bonded wheel or canvas wheel you'd be in for a tragedy. The wheels would catch your knife and throw it. It Happens. It happened to me. I have the scare right on my wrist to prove it. 'Came close to the artery, just missed. Pretty scarey stuff. I had ment to turn the grinder around but hadn't got around to it yet. I made a momentary bad judgment and sharpened into the blade and instantly had a projectile flashing past my arm. Forewarned is forearmed or something like that.
The rubber bonded wheel has abrasive particles in it which are great for polishing the scratches out of steel. It is also excellent for quickly putting a very good edge on knives. It will generally raise a feather which I remove by drawing the blade through a piece of wood. I finish off by polishing with the canvas wheel loaded with a polishing compound. The compound comes in stick form with minute abrasive particles embeded in a wax.
Remember to alway sharpen with the cutting edge of the spinning wheel travelling away from you AND remember to keep the blade edge of the knife, scissors, etc., facing away from you.
"I use a jewelers 16x magnifying loop to inspect the edge under good light. Any deficiencies can be easily seen."
"I have had my own sharpening business since 1984. I sharpen by hand, Japanese style with water stones and I use DMT stones also. One personal technique that I use not mentioned in your tips is that I rub the knife on the stone (often in small circular motions) until I feel a burr on the other side, then I know it's time to do the other side."
Bruce Wagner on using oil with a diamond sharpener:
The ... Jewel Stick sharpener I saw demonstrated this past weekend. I was surprised that the guy demonstrating them was using baby oil on them. He sharpened all 3 knives I had with me at the time, and I couldn't argue with the results. I bought a bottle of baby oil and tried it with my Ultimate Edge 5" oval sharpener, as well as my DMT course and fine Diafold sharpeners. After sharpening several knives using this method, I'd have to say I'm impressed. According to the Jewel Stick salesman, this floats the metal particles and keeps them from clogging the pores between the diamond particles. This is completely contrary to the instructions provided with these sharpening devices, which state that only water should be used, but darned if baby oil doesn't make a noticeable difference in their performance, far better than using them dry or with water. It should also eliminate any problems with rust developing as I've heard can happen if people don't dry them carefully after using with water.
On Types of Oil to Use:
Canola oil is a good substitute for petroleum based oils if you are going to use your knife to cut foods. It is not harmful, unlike petroleums and synthetics. There is also a product called Ballistol which is supposed to be harmless for food preparation areas. I tried olive oil but it dried out on me and gummed up the knife. Canola oil seems to stay thin. Soap and water will clean it out if it does thicken up over time.
One method for keeping track of your sharpening by Jim Himanga:
Mark the edge of the knife with an black indelible magic marker before starting the sharpening process. The marker comes off on the areas that touch the stone, so you can check to determine how consistant you are in holding the angle constant and if all of the edge is being sharpened to the same degree. You can reapply the marker during the process to continue checking. Oil will remove the marker when you have finished.
(KnifeCenter Note-Please Use Extreme Caution When Using Electical Appliances on a Hand-Held Blade)
From France we got this message:
I am a French stage manager, and I use my Gerber knife quite often. Every week,or so, I put in a drill held into a vice a large (about 10"), wide (about 1") hard felt wheel. I prepare it by spinning it and applying a coat of polishing paste commonly used by car buffs.
Then, it's just a matter of selecting the proper spinning speed, and keeping the blade properly angled against the wheel. I can keep it razor sharp that way, but it doesn't work for totally dull edged blades: they have to be prepared by more traditional ways. Hot weather, or continuous friction tends to lessen the quality of the results as the heat tends to melt the coating of burnishing paste.
My way keeps it honed and smooth as it polishes at the same time. What's more, it's effortless, if a little noisy. Hope my English is clear enough.
The Following Sharpening Tips are Personal Opinions Furnished by Dale A. Ferrier
These are personal opinions and methods and are not necessarily endorsed by or recommended by the KnifeCenter or any of the manufacturers or suppliers of sharpening products.
Note: All the following were gleaned from the bible of knife sharpening called "The Razor Edge Book of Sharpening" by John Juranitch published by Warner Books
- The specific angle is not as important as keeping a constant angle.
- When using the rough grit stone use a shallower angle than when using the fine stone. That is, grind the (usually) sorry factory edge to a shallow angle with the rough grit stone and I want to stress here that there is no special way to do this because you are just removing useless stock from the blade. Just grind one side of the blade until it is ground down enough. What is enough? Well enough is defined like this: Once you have ground the blade down enough (maintaining the same angle all the while) to have touched the cutting edge, start to test the edge on the opposite side of the blade by running your finger nail at a 90 degree angle to the opposite edge moving from the back of the blade towards the edge. Why? Well you are trying to find the curled edge (or burr) created by the grinding down of the first edge. Once you have this curled lip along the edge from tip to tang then turn the knife over and begin grinding the other side until you have the same curled lip for that side. Once you are done you should have a roughly ground edge with a fairly shallow angle.
- Now take your fine grit stone (at least 400 grit or finer) and raise the angle of the blade you just ground down by just a little more and using moderate pressure make a single cutting stroke maintaining as much as possible the same angle down the stone making sure to sharpen the whole length of the edge on the stroke. Now after one single stroke turn the knife over and repeat the same process. Do all this slowly and deliberately. Repeat this about 6 times and then begin to lighten the pressure on the blade as it strokes the stone. At about the 10th or 12th repetition about only the weight of the blade should be pressing on the stone.
- IMPORTANT! Do not use water or oil of any kind on any stone to sharpen your knife. In fact if you have been using some liquid on your stone, wipe it off as best you can or get a new stone which has not been tainted with such a substance. I know this goes against years and years of trusted advise from friends, fathers, aunts, uncles, grandfathers and etc.... Trust me on this one. Read the book to find out why this is true.
- After step 3 test the sharpness (carefully) by cutting a sheet of paper or (even more carefully) trying to shave a few hairs off your arm. If you followed step 2 faithfully you should have an almost razor sharp edge. If not then re-read step 2 and do it again from the course stone. Step 2 is most important. Step 3 actually does the sharpening.
- The more highly polished an edge the better it cuts. "Teeth" does not a razor edge make.
Well this ran into quite a lengthy discussion. Sorry for that but even if you have grave misgivings about this simple method for sharpening a knife at least try it once. I am confident you will never go back to however you were doing it."
The Following Sharpening Tips are Personal Opinions Furnished by another Individual
"I find best results for carbon steel blades are:
Sharpen with coarse friable arkansas stone until there is no glimmer left to the edge when vieed under bright sunlight. Refine edge with a few strokes on a smooth stone to polish the edge.Strop backwards on cotton twill ca. 10x alternating sides at ca. 30 angle.Test by dry shaving back of hand.But above all - PLEASE be careful!!!!"
NOTE: The preceding are personal opinions and methods and are not necessarily endorsed by or recommended by the KnifeCenter or any of the manufacturers or suppliers of sharpening products.
Know any good knife sharpening tips or tecniques you would like to pass on to others? We'd be happy to hear them- simply click here to e-mail them to us.