Tools for Working Wood
Invest in your craft. Invest in yourself.

 Joel's Blog

Feel The Burr  

06/29/2010



The simplest way to sharpen something is to create a burr or wire edge and then gently remove it. What's left is a sharp edge. You can read step by step instructions for sharpening here. We also stock two videos on the same subject. Here - oilstones and here - waterstones. The question of the moment is how to find out if the edge is sharp and the wire edge has been completely removed. The simplest way to do this, a far more reliable method than using a microscope or anything - is to feel the edge of the blade from both sides. If both sides of the edge feel the same and equally sharp - sharp, the edge is sharp with no burr. Your fingers are incredible sensitive and can easily feel something as thin as a human hair or one sheet of paper on a table. The trick of course is training your fingers to feel the burr. Here is how you do it:

With the chisel held straight up, gently hold your finger straight against the blade and pull your figure slowly straight downward (top picture). If the blade is sharp and you have a light touch you will feel a sharp iron catch in the ridges of your fingerprints. A dull iron won't catch, and if there is a burr you will feel it or, at the very least, doing the test on both sides of the edge will feel differently. The close-up gives a slightly better view of how lightly the edge is dragging against the fingertip. Whatever you do - don't go side to side on an edge - you will slice your finger wide open. If you move your finger up against the iron, not down, it looks safer but far less information about the edge can be felt. Going in the direction of the arrow is perfectly safe as long as you use a very very light touch.

Then what you do is flip the iron over and do the same test on the bevel (last photo). When you chase a wire edge or burr the burr will flip over from side to side as it's abraded, when you can't feel a burr on either side of the edge, and both sides feel the same you are basically done.

If you follow our sharpening recommendations of stropping on a plain piece of leather you can feel, as you strop the edge getting less grabby and smoother, this is because the very last bits of the wire edge, that you can't see, and barely feel are being removed. At this stage a strop with honing compound on it will simply create more wire edge and should not be used.

It's a very simple technique, I urge you to try it but I must mention one warning. In theory it's trivial to do this, in practice it took me a little while to get a sense memory of what a really sharp edge is like. So initially you have to pay attention and practice. It's the best way I know of checking an edge, and far, far faster than figuring out where your microscope is and getting the light just right.
Tags:Woodworking Tools and Techniques
Comments: 1
09/01/2010andrew sacco 
learning alot thanks
Comments are closed.
The opinions expressed in this blog are those of the blog's author and guests and in no way reflect the views of Tools for Working Wood.
Subscribe
 Joel's Blog
 Video Roundup
 Classes & Events
 Built-It Blog
 Work Magazine
Recent Blogs:
An Introduction to Hand Tools - The Instructor Confesses - 10/11/2017
Ten Ways I am Doing Things Differently - Part 3 - 09/27/2017
Ten Ways I am Doing Things Differently - Part 2 - 09/20/2017
Ten Ways I am Doing Things Differently - Part 1 - 09/13/2017
Dovetailing Classes: a New Approach - 08/23/2017
MoMA's Lost History of Woodworking and Craft Classes - 08/09/2017
The Hardware Store Saw - The Long and Short of It - 08/02/2017
Dovetailing - Removing Waste - 07/26/2017
10th Anniversary Post!!!! - 07/19/2017
A Mid-Century Modern Bookcase - 07/12/2017
Teaching Dovetailing Skill - 06/21/2017
Father's Day - The Gift of Learning - 06/14/2017
Woodworking with Kids (Special Father's Day Edition) & Other Ways to Celebrate Father's Day & Posters - 06/07/2017
St. Monday and the Sharing Economy - 05/31/2017
Plane Spotting for the Deeply Curious - 05/24/2017
A Sense of Community - 05/17/2017
Amana Here We Come! - 05/10/2017
OMG - 16th Century Boxwood Miniatures PT2 - and other news - 05/03/2017
OMG - 16th Century Boxwood Miniatures PT1 - and other news - 04/26/2017
Spooncarving and News - 03/29/2017
Older Entries...