How To Sharpen a knife

The Edge

The ways to sharpen a knife have been covered in detail and great length by so many, there is not much to add in the way of "how to". I would like to explain the methods I use though so users of my knives can get the most out of the blades edge.

The primary edge

In a nut shell, the technique is as follows:

Hold the stone or rod in a safe manor and repeatedly attempt to slice off thin shavings of the stone in both directions exactly as you would if you were shaving the bark off of a small stick. This will take your mind off getting the angle right and let you focus on the task. The angles will be what you are used to and the knife will be sharpened for your cutting style.

The Details

The type of stone plays a drastic role in the end result of sharpening. I prefer diamond and ceramic stones and rods. Both should be very fine. These types of sharpening devices cut away steel faster than natural stones and do not need to be coarse. Other reasons I use these over natural stones is because they do not need oil and the natural stones tend not to cut as well on certain high alloy steels. Steels that are very hard or have several carbide forming elements in the alloy cause the blade to glide over the natural stones surface. The simple steels work very well with natural stones and experts can still get good results with high alloys, but I like the stones to be as hard as possible to speed things along. It should also be known that the diamond stones need to be heavily broken in. Since the diamonds are bonded to the surface in an application that leaves the very top partials loose, I will literally take an old file and rub a new diamond stone vigorously to rub off any loosely attached particles and smooth out the surface and make it as fine as possible. Ceramic stones and rods need very frequent cleaning to remove the metal deposits from the pores of the surface. This is best done by scrubbing with a special eraser but the ones sold today don't work as well as the ones sold in the Eighties.

If a delicate, sharp, needle point is very important to you, consider this. As the knife is sharpened on a rod, the point will get to the rod at the end of the stroke. If pressure is maintained through out the stoke, the point will travel down and around the side of the rod. this will wipe the point off after several passes but for the most part it won't matter much to daily tasks and the Crock Sticks I use are a fast way to get to a very fine edge.

The Fine Edge

Now that you will be able to get to the primary edge, lets see how to refine it, preserve it, and maintain it.

The fine edge is where the two planes of the edge actually meet in the cross sectional view and this is where the cutting takes place. This is the most delicate and the most sanctified part of the knives geometry. It is crucial that the design of the actual fine edge complement the use of a knife. If the knife is being used with harsh chops, the fine edge will not hold up if it is honed too fine or the primary edge is to acute to support the fine edge. The more acute the edge is the sharper and weaker it is. The more obtuse the edge the harder it will be get it sharp and the harder the task of cutting will be for detailed work and skinning game. Since knives need to be able to do many kinds of work, a specific use of the tool is not always factored in to the edge design. Nowadays people want do-it-all knives. A woodsman may be making camp one minute and cleaning game the next so the edge winds up being a compromise of the best attributes for the most types of tasks. The knife must cut well in soft and hard medium and be tough enough to handle hard use in a pinch.

The edge will not usually be satisfactory if the fine edge is left with what is called the wire edge. The wire edge is the lip of metal that rolls up and away from the sharpening stone as the blade cuts across the surface of the stone. It is hard to see but makes a big difference in cutting. Until the wire edge is polished off the knife will not cut very clean and will get dull faster because the wire edge is rough, unsupported and off to one side.When the edge is polished it will be as strong as it can be in the given condition. This is because the steel is smooth with less affect from abrasion. If the edge is smooth it will glide through the medium with less effort and less chance of the metal of the edge being rubbed away. Any scratch marks left from the stone will be like small edges themselves. As they get dull the edge changes dimensions and form making the edge dull overall. Make the last few strokes across the stone with lighter pressure and then move on to a finer stone.

After the wire edge is removed as well as can be by the stone, stropping the edge on leather or a special surface with polishing compound will give the edge the gloss it needs for a proper edge. One fast way to accomplish this is with a buffer, but this takes some practice so you don't buff the whole edge off. There is a proper way to strop an edge. The way seen in movies and by most people today is the wrong way. The edge is dragged down the leather strop then at the end of the stroke, the blade is rotated spine up first and flipped over for the opposing stroke and then flipped again spine up first. This rolls the edge across the polishing surface and rounds off the edge. The proper way is to pick up the edge first and flip backwards to keep the edge off the polishing surface during all movements except that which is for polishing the actual edge. This way the edge stays as acute as possible for a very sharp edge.

I hope this is some help to those who have had trouble getting their edge right. I'll post some pictures when I can of some equipment and techniques.






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