Posted by: woodbeecarver   in Knives

KNIVES USED FOR CARVINGThe WOOD BEE CARVER grew up with the pocket knife being used for whittling and when it comes to carving, refurbished, reshaped and sharpened pocket knives are still the first choice.  The pocket knives depicted in the photo show the shape of blade preferred for its slicing action ability and getting into tight spots.  Of course it all boils down to what one gets used to using and personal preference.

The small bladed knives in the photo above were made from broken blades reshaped and sharpened.  The larger bladed knives in the photo began life as a pruning knife with a hawk bill or hooked blade.  To get the shape as they now appear, the blade was cut to shape using a cut off disc on a Dremel Tool on what is now the back edge of the blade. 

The sides of the blades were shaped flat so that when both sides meet at the cutting edge the blade forms a thin and sharp “V” bevel from the cutting edge to the back edge of the blade.  This shaping, which prepares the way for sharpening is done by hand using diamond plates that look like a credit card, beginning with 200 grit or coarse, moving to 600 grit or medium and then 1200 grit  or fine.

In earlier years I used a medium carborundum stone to do the initial shaping, then moved to a fine India stone and then a hard Arkansas stone.  But in recent years, the diamond metal plates seem to do the job just as well and are easier to carry in a tool bag to be used at any time.  In the shaping phase the blade is laid flat on the abrasive surface and rubbed back and forth while keeping the blade as flat as possible.  This is done to both sides of the blade until a good burr edge appears on the cutting edge.

This procedure is to thin the blade while at the same time removing any secondary bevel so that when a burr edge begins to appear on the cutting edge the two flat sides become one long bevel from the cutting edge to the back edge of the blade.  Once there is a good burr edge along the entire cutting edge, the procedure is repeated on the next finer abrasive which will make the scratches on the side of the blade smaller and the burr edge smaller.

Next, the finest abrasive is used, once again keeping the blade flat while rubbing the blade back and forth on the abrasive making the scratches on the side of the blade even smaller and the burr edge finer still.  The final dressing of the blade is to strop it on a leather strop loaded with an abrasive compound of aluminum oxide or chrome oxide or jewelers rouge.

The sharpening acting is pushing the cutting edge of the blade into the stone while the stropping action is pulling the blade across the leather strop in a backward action.  The stropping action continues to polish the sides of the blade and rubbing off the burr edge and polishing the small cutting teeth that make up the cutting edge.

The cutting edge is very much like little saw teeth that work best in a slicing action.  The shape of blade preferred has the cutting edge curve slightly up to meet the back edge of the blade at its tip.  This shape of blade has both a section that has a straight cutting edge and then at the tip where it curves up, it becomes a skew cutting edge.  Many other carving knives have a straight cutting edge with the back of the edge curving down to meet the point of the cutting edge or commonly called a wharncliffe blade.  That blade works just as well as long as it is sharp, but it still boils down to personal preference and what works best for the carver.

The corners of the back edge on all carving knives should be rounded off in order to ease the blade coming out of the wood in a tight turn.

The carving blade does at least three things as it slices through the wood.  The cutting edge, when sliced, separate the wood fibers while the bevel running up the side of the blade spreads the chip away from the block of wood and the polished side of the blade burnished the wood as it passes between the chip and the block of wood.  If the side of the blade has visible scratches from rubbing across the abrasive then those scratches cause friction and resistance when the blade passes through the wood being carved resulting in a dull, non-burnished surface.  One of the purposes of stropping is to polish away visible scratches while the teeth on the cutting edge are also polished.

Sharpening is one of those trial and error exercises of learning by doing and sharpening is one part of the carving process.  Every carver should experiment and learn to do their own sharpening for it is a part of the journey of wood carving.

This entry was posted on Saturday, January 5th, 2008 at 11:12 pm and is filed under Knives. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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