Thread: What Exactly Is A Burr?

Over the years I've read numerous posts and articles mentioning a "burr" in relation to honing. However, I've never come across a clear definition of what a burr is. Can you gentlemen help me understand what a burr is?

When you put a lot of pressure on your blade when you're honing in a low grit and you go way overboard, you might wear down the edge enough that it produces a tiny wire edge running along the cutting edge. I've never seen one in my own honing.

Hey There

Burr with relation to a shaving edge is the protrusion of microscopic (or sometimes even macroscopic), pieces of metal outside of the cutting edge, sometimes called a "wire edge" as mentioned. There are other definitions of burr but I think this would be most relevant. If you take a look on

http://www.coticule.be/stropping-a-straight-razor.html

they show SEMs of the razor edge after honing and before stropping. There is something that could be considered a burr, but it doesn't really protrude outside the edge. Stropping can help pull these small pieces of metal into line with the cutting edge, but as they state in the link it won't last very long. This is one of the reasons why you need to strop before every shave.
So ... Everyone hates Wikipedia, well wiki actually has a pretty simple article on this

Burr (edge) - Wikipedia, the free encyclopedia

The reason a burr can form when you are honing (or even a micro burr like the coticule website talks about) is because you are removing steel from the razor. You are basically tearing it from the main piece using abrasive rock (or synthetic). This can leave small serrations behind, that will be smaller as the hone gets finer.

A more blatant burr can be seen if you grind steel on a grinding wheel. It can be clearly visible to the naked eye.
That is how I see burrs ... anybody else?

Thanks

Carl - straightrazorheaven

A scottish guy's accent...

Originally Posted by TheLegalRazor

Over the years I've read numerous posts and articles mentioning a "burr" in relation to honing. However, I've never come across a clear definition of what a burr is. Can you gentlemen help me understand what a burr is?

Actually, a burr has no relation to razor honing. It is more related to grinding or extreme restoration of edges where multiple strokes with pressure on one side may push steel over the edge, to use a pun.

He's the dude that shot Alexander Hamilton.

Originally Posted by onimaru55

Actually, a burr has no relation to razor honing. It is more related to grinding or extreme restoration of edges where multiple strokes with pressure on one side may push steel over the edge, to use a pun.

This is how I see a burr as well, exactly. Now you can produce a large detectable burr on a razor, but mostly I think it is mixed up with overhoning/wire-edge, as a term in language. Although very small burr occurs at all levels of honing (the little particles that are holding on to the edge), the more serious concern is a wire-edge/overhoning or crumbling edge when the edge becomes too thin.

I think everyone (including me) is saying more or less the same thing.

In knife sharpening it is frequently recommended that one should sharpen one side of the blade with a low grit until a burr forms.

This is when you remove enough excess material from one side until it moves over to the other side. In other words you are sure you have brought the two sides together (in a V) as close as you can get.

You then grind the other side until a burr appears on the first side.

After this you progress through the higher grits. You don't really create the same kind of burr after that at each stage (it depends on your definition of a burr after this point).

From this point on most people refer to "micro-serrations" rather than a burr. Really now you are just honing by "scratching" your edge with finer and finer "scratches".

With razors I think rather than speak in terms of "burrs" it's probably more accurate to most people's way of thinking to talk about "micro-serrations". Going for a "burr" regarding razors is probably unnecessarily destructive or wasteful of edge material.

Until you have a perfect polished edge (which I assume never technically happens) you have finer and finer micro-serrations.

That's how I view this subject in any event. I'm already open to being corrected however.

A burr is something us Canadians say during winter, usually followed with time honoured "Cold enuff for ya?"

Here

For a good test and definition of actual Burrs on an edge watch this Vid from Toxik, in there he is going to teach you the "Pin Test" This is a very good way to define the difference between a Rough/Chippy/Micro-serrated edge and a Burr/Wire edge.. Starts at 2:25 in

https://www.youtube.com/watch?v=XZYFsOP7rBc

This is one of the lines that is drawn between Proper Honing of a straight razor and the Ham-handed "It's just a tool" attempts of other sharpening.. If you draw a Burr (Other then during REAL restoration) then you have gone right past the ideal point of Bevel Setting and you need to Back stroke and re-define and set the bevel..