Stropping

Stropping

The final step in the sharpening process is stropping.  There are many different methods that are effective;  By hand using leather is one of the most popular.  A piece of horse leather fastened to a board is an option for flat and convex angles, but to get into the concave part of a gouge, you need to have a loose piece of leather that you can fold over or around a dowel to strop a concave edge.

I prefer to use a powered system - it allows me to concentrate more on stropping the edge both more effectively and more evenly across the cutting edge.  Options for powered stropping system include using a wheel on your grinder made from cardboard (glued together cardboard from the backs of notebooks - one of my favorites!), MDF, muslin, or felt... my favorite is leather.  It's soft enough to hold a honing compound, yet hard enough that I can concentrate on the edge of the tool without worrying about the strop deforming and rounding the edge over.  

There are several ways to get one - 1"x30" belt sanders have leather belts available for them.  There are leather wheels made to fit into a drill.  Of course, there's also the Tormek and similar systems.  An important note for power users, and that is to make sure you always put the trailing edge of the tool you are honing where the wheel is turning away from you, like how it's oriented in this illustration:

Some advocate using clean, undressed leather for a strop - as the ultra fine arkansas stone leaves a good enough edge.  I still use a bit of honing compound on mine, as I believe I still get a better edge.  This might not be true if you are stropping the edge by hand, I honestly don't know...  I think it definitely calls for some experimentation on my part.  In any case, I'll continue on with what I do know, and that is using the large flat leather wheel for honing all my flat and convex edges, slowly rotating the tool until the entire edge has been stropped:

That still leaves the inner, concave edges of the gouge left to be stropped.  I use the optional shaped leather wheel, lightly coated with honing compound, to work just the cutting edge of the tool.  In both these instances, I use very little angle to the strop - I don't want to round the edge over, which would dull the blade and defeat the purpose for which stropping is used for.  Just strop enough to remove the burr formed while polishing the stone on the hard arkansas stone and to give the very edge a nice, shiny appearance.

In reality, power stropping takes very little time.  I probably spend all of about 5 to 10 seconds at most on each side of the edge.  The final product shows just where I concentrate on stropping the edge:

Note the shiny part of  the metal right at the very cutting edge.  It's the only part I worry about stropping.  All stropping really needs to do is remove the burr that was formed in the last step.  Trying to do more than that can be counterproductive, and runs the additional  risk of accidentally blunting the edge.  There's no need, in my opinion, to do so anyway.   All I am really concerned with is how it cuts.  

With repeated honings, the edge will become more blunt and eventually require touching up on a stone.  Which stone will depend upon how dull the edge has gotten.

You can see that I've even left some of the grinder marks in the center of the bevel, at the bottom of the hollow grind left from the round wheel of the grinder.  They don't hurt the performance of the tool any, and removing them just means I'm removing more steel - which in essence is simply shortening the life of the tool, no more.

Flipping the gouge over, you can see how I only strop the cutting edge of the concave part of the gouge:

It's very little - as I mentioned before, this length would be more if this was a carving tool, but since it isn't I decided to stay with the original edge, and not bevel it any further than I had to.   A carving gouge is called on to be more universal in nature, and I all ready have some sharpened in that manner - a little diversity never hurts.

Testing the Cut

Here's where you can "test your metal" to see how well a job you've done. I take a piece of scrap wood, and run the gouge perpendicular to the grain.  If I see results such as these, I know I haven't done my job well enough:

A sharp edge will slice through the wood cleanly, with a satisfying "hiss".  I've tried to enhance the above photo a bit to better show the tear out left by a dull gouge - hopefully you can see where the gouge has crushed and tore the fiber on the right side of its cut.  Seeing this would tell me the right side of the blade was still too dull, and I would go back to the ultra fine arkansas stone and start over from there.

The kind of cut you should be getting should look more like this:

Nice, even edges, and not a bit of tear out all the way from one side to the other.  This gouge is ready to go to work.