How do you know if a tool is sharp?

[whittlinwit]

Since this is beginners carving, I thought I might give some beginners advice.

A tool is sharp when the finished cut is clean and shiney with no white streaks or haze.

A sharp tool may still be difficult to carve with if the grind is incorrect or the tool is too thick.

[richy-ruff]

Re: How do you know if a tool is sharp?

I know mine is sharp when I send it to Rick-in-Seattle to fix it.

[don]

Re: How do you know if a tool is sharp?

No, when you send it it is dull, when you get it back it is sharp. Don

[richy-ruff]

Re: How do you know if a tool is sharp?

I guess I can answer this question now with some level of knowledge. You know if your knife is sharp when it goes into your arm about an inch and a half, cuts an artery and does damage to some muscle. This is what I did on thanksgiving while cutting the top off a pumpkin. I think I damaged my immage as a seasoned carver more than my arm. :-/

[Hi_Ho_Sliver]

Re: How do you know if a tool is sharp?

That's an 'OW'!...but you realize...you damaged a seasoned pumpkin too! :

[Hugo]

Re: How do you know if a tool is sharp?

Rick, I have a question for you. On my favorite carving knive I have developed a micro bevel. I'm not really sure how I managed to accomplish this unremarkable feat. Can this be caused by putting too much pressure on the blade while stropping?
Sadly, I know that the solution involves a ceramic stone and some elbow grease. :-[

[Whittlinwit]

Re: How do you know if a tool is sharp?

Hugo,
What you are talking about is called a secondary bevel.
It creates resistance to the point where it becomes necessary to hone the blade back to it's original configuration.

When using a stone, especially one that is too fine, we become impatient and raise the heel of the blade to get a sharp edge quicker. That is normally the cause of the secondary bevel. The situation becomes worse each time you sharpen, because you must raise the heel higher each time to get a sharp edge.

The solution is to re-shape the sides of the blade to a nearly flat surface. This takes time, but is well worth the effort.
Start with a course stone or wet-or-dry sandpaper; when the surface begins to look flat, switch to a finer grit to finish the edge.

To answer your questions about stropping;
Stropping will tend to create a round convex bevel rather than a visible secondary bevel.

Can stropping cause a problem?
It will depend upon your strop, and your method of stropping.
If the leather is thick, it can tend to wrap-around the cutting edge and round it off if too much pressure is applied.
Keep the blade nearly flat on the leather and raise it at the end of each stroke.

Good luck, Rick

[Mr._Munchkin]

Re: How do you know if a tool is sharp?

I have three tests for sharpness. First: if the blade can make a polished cut on end grain, it is sharp. Second: if I can set the blade perpendicular to my thumbnail and, without exerting any downward force, feel the edge catch, the blade is sharp. And finally: if the I can use the blade to cut a sliver of paper finer than a thread, then the blade is definitely sharp. I used to try to shave the hairs off my arm, but not only did it make my arm look funny, but also it got a bit messy with gouges :

[big_Wayne_P]

Re: How do you know if a tool is sharp?

I know they are sharp when they cut without any resistance at all. Better still just touch the cutting edge o the tool and if you bleed just by touching the tool then it is sharp[/color]