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The  Channel Scraper Tool for Violin, Viola, and Cello
Sharpening Instructions

The Channel scraper comes pre-sharpened. I suggest trying the tool as delivered on some scraps of wood before shaping the blade to your desired channel profile. This will show you how easily the tool cuts when sharpened properly.


There are many methods and techniques to sharpen a scraper. For the channel scraper blade, the cutting edge must be at 90 degrees to the length of the blade for the scraper to effectively cut in two directions. The blade is made from a HSS (High Speed Steel) hacksaw blade. Here is a sharpening method that works consistently.
 

1. Shape the end of the blade to the desired channel profile at the C-bout. A pedestal grinder or a disk sander are the tools of choice here. Avoid getting the cutting edge too hot. (Too hot and the blade will lose it’s hardness.)
 

Blade End Profle

 

2. Flatten the sides of the blade on a stone by moving the blade in one direction only, away from the cutting edge. A medium Arkansas or similar oil stone is preferred for the sharpening process. ( Note: Many water stones have a soft bond and may round off the cutting edge.)
 

Flatten Side of Blade

 
3. The objective here is to create the right size burr on both sides of the blade. Too small of a burr does not cut well, nor does too large of a burr. Position the blade at 90 degrees to the stone. With light pressure, move the blade back and forth while rocking  the blade along the channel profile. Be sure to keep the blade at 90 degrees. After a few seconds, check the scraper for sharpness. I use a fingernail to check if the blade is sharp. If not sharp, repeat this stoning process a few more seconds. Check for sharpness. Repeat stoning until sharp.

  The burr that is left from the stoning process is just right. I find that burnishing is not necessary and may actually be counterproductive.  I have measured the size of the burr on scraper blades that cut well with this tool. The burr size is less than .0005”( that is less than 1/5th of the diameter of a human hair).
 

Move back and forth while rocking.

Create Burr

The video below demonstrates sharpening the blade for the Channel Scraper Tool.

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