How to sharpen tools.

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Their are a million ways to sharpen tools. Their have been many books about the subject. On this page we hope to have some tried and true ways. Some ideas from books but mostly help from our members; How they do it. So come back often to this page.

Gary Stutts

Knife Sharpening; By Paul Hawkins

Like many other jobs, there are difrent ways to sharpen a knife. I am of the opinion that one should use the method that works best for you. The method also depends on how dull the knife is.

I like using auto wet/dry sand paper and a leather strop loaded with the green polishing compound when you are just touching up the edge. To make a good touch up sharpener, rip a piece of wood about 1/4 X 1-1/2 inch about 12 inches long. (a piece of a yard stick is good) Remove rough cut by sanding with about 220 grit sandpaper. Apply a light coat of carpenter glue to the wood. Lay the wet/dry sandpaper with rough side down and align the wood with the sandpaper. Clamp the sandpaper and wood to each other until glue is dry. Cut sandpaper with a utility knife, using the wood as a guide. Sometime I apply another grit to the reverse side of the wood or a section of leather to use as a strop. Carpenters glue is also good to glue the strop.

To sharpen the knife, lay the blade FLAT on the sandpaper. Raise the back of the blade about the thickness of a dime. Pull the blade in the opposite direction of the cutting edge maintaining that angle. Be careful not to further raise the back of the blade during the stroke, which will defeat our purpose. Repeat this stroke for 3 or 4 times, then go to the other side and do an equal number of strokes. Try maintaining equal down pressure on each stroke. When you feel a good sharp edge on the knife, move to a finer grit or to the strop.

Load your strop with your favorite compound (green, white or red as they are of different grit). As with stroking the blade on sandpaper, be sure to lay the blade flat, raise it ever so slightly and pull away from the cutting edge. Reverse sides and repeat the same number of strokes.

I would like to share a story one of our club members related to me about 17 years ago. This member was giving me 1 on 1 instructions in sharpening. I ask, how often do I need to sharpen my knife, to which he replied just before it needs it. Although it sounded odd at the time, I find he was exactly right. Its much wiser and easier to keep it sharp. When stropping the blade, he also stated; The blade not only must be sharp, it must be polished so it can glide through the wood with ease.

If the knife has been dropped, gaped or otherwise abused, I like using the diamond steel sharpeners to get back to a good edge. They are available in different roughness. While a power sharpening device removes steel much faster, many times its too fast and also heats the steel, removing its temper. After using the diamond steel, go on to the sandpaper/strop to finish.

Power strops and sanders work well to maintain sharpness. These are dangerous to use. Be careful to keep the rotation away from the cutting edge.

Good luck. Paul Hawkins

 


 

Knife Sharpening; (Don't know who wrote this; I think they are from the UK.)

When I first started to teach adults at an evening institute class, I soon realised that sharpening was going to be the big stumbling block for many of these would be carvers. Many of them did not have oilstones, and were hardly likely to invest in them for an interest that could well wane in a short space of time. I tried to think of an alternative to the oilstone, and came up with this idea. Wet and dry emery paper. It’s cheap, easy to get, used dry it’s clean and on a flat surface is always flat. So. This is my way of sharpening now. I have done it this way for many years, and it is what I advocate to my pupils, even to those with oilstones.

Buy grades of emery paper in 150 grit, 350 grit, 600 grit, 1200 grit and buy a tube of chrome cleaner paste. I fix these sheets of emery onto a piece of plastic coated chipboard (called melamine coated in the UK), side by side, with masking tape. I use white plastic covered board because it is so flat. Ordinary chip board is not flat enough. MDF board would be flat enough, but when I started doing it this way, that was not about. I either wedge it on the bench or clamp it down with a g-clamp. I tear a sheet of emery paper in half so that I have an A5 sized sheet and stick it down onto a 6 inch wide board. I only put masking tape on three edges of the sheet, which are end to end on the board, and I have one edge of the paper right on the edge of the board, so that this edge can be used for a knife, with no masking tape on this edge.

What we have now is four grades of abrasive that will always be flat. Oil is not needed, and the only difference is that tools are sharpened by pulling along the emery and not pushing. The technique used is to roll the curved gouge from side to side across the paper, holding it in one hand and pushing down on the shaft with the two fingers of the other hand. This assumes that the end of the tool is level, although I like there to be a slight cut back in the middle of the cutting edge. The opposite of how the end of a finger looks, if you follow me. Not as much as that but just a slight cut back.

The tool is rubbed from side to side, twisting the tool with the ‘holding hand’, and stopping the twist just as the corner of the tool is reached. Starting with the finest paper required to make an impression on the tool. Usually starting on the 350 is coarse enough. The tool should be held at the angle you prefer when you carve, (I like about 30 degrees). The work done on each tool can easily be seen, and by moving across the sheets of emery going to a finer grade each time, the tool will soon become sharper, as it becomes shinier. I use a magnifying glass to see how sharp the edge is. If you can see the cutting edge then it is not sharp! After using the 1200 grade it should be very sharp, but will need to be stropped, and this is best done using the chrome cleaner paste on a piece of leather, which can be stuck alongside the emery, on the end of the board. Use a piece of leather with chrome cleaner on it to rub the burr from the inside of the cutting edge. Just fold the leather to fit the inside curve of the gouge. For the V tool, use the edge of the leather strip on the inside of both flats. I never put an inside bevel on tools that are going to be used on the softer woods, especially when they are going to be used without the aid of a mallet. For hard woods and mallet use, I have a set of tools that have a bevel on the inside, to help the cutting edge last longer.

The tool will now be super sharp, and the emery is still flat for use with the next tool. Tools should only ever require use of the 1200 grit and the strop during normal carving, and the full treatment if they get nicked. When the emery paper is worn out then it can be replaced with a new piece, but bear in mind that it has now become smoother than before, so it is still useful. Usually all that will be required as you carve is to use the strop from time to time.

Now to the V tool. This is best treated as two flat blades, that happen to meet at the bottom. I grind the front edge so that, when the tool is held horizontal, the front edge is raked back just like the prow of a ship. Not too much but just enough to notice. Now hold the tool as above on one of the flat sides and pull it back towards you. Do this until the cutting edge is sharp. Now the next bit is easier to show than it is to explain. The tool must be held at angle of 30 degrees to the paper, but at a 45-degree angle to the line of pull. You need to cut away the area where the two sharp sides meet at the bottom. So, with the two fingers pressing down on the blade need to press down with the emphasis on that corner. The holding hand can help by very slightly twisting the blade to bring the corner to bear on the paper. The action is to slide the tool across the paper, while maintaining the twist and the pressure. This will cut away the metal at the bottom point and will start to form a secondary bevel at this point. Most V tools, due to the way they are formed in manufacture, are thinner where the two sides meet, and often when sharpened there is a point formed at the bottom of the cutting edge, which protrudes out. Traditionally this point is rubbed away and the underside is rounded over. Why bother? This point is sharp, and so is the bottom edge, so why undo all that sharpening? As you sharpen the tool you will see the sharp edge and the cutting bevel start to form. Using a magnifying glass, you will see that the point is just as sharp as the rest of the cutting edge. Use the strop to get the secondary bevel to a shine, with no scratches on it…mirror shiny is how all you bevels should be, right to the cutting edge. Any scratches will mean the cutting edge is not as sharp as it can be.

To maintain the cutting edge while you carve, you might like to try the Cratex Extra Fine Block. The XF one is ideal to keep the edge keen if you feel it is getting dull as you work, and a few strokes with the block usually restores the sharpness. The fact that cratex is used without either oil or water, means it can be used anywhere, and kept in your pocket, for when you need it. The block is made of a hard rubber impregnated with silicon carbide so it can be bent and carved to suit gouge shapes. It does not break if it is dropped, unlike arkansas stones. The only draw back is that over a period of time, after many rubs, the flat surface of the bevel may become rounded, and then it will require re flatting on the papers.

This is a totally different way to sharpen against the traditional methods, but I have been sharpening this way for many years, and it works. Try it and see what you think.

It is possible to buy 2500 grit paper now, and this will give a polished surface almost as good as a strop.

 


 

 

© 2009 SCWC ; Melbourne, Florida