how do you know if its sharp

S

sasha

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Feb 28, 2006
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O.k i been reading alot about the convex and how to put it on a knife. I have a very old collins 1 1\4lb. So i took the file and filed it down. It had 1\8 edge on it so i reprofiled the axe so it was smooth with the head. Then i took a 220 grid sand paper on some thick cloth. I worked it going back for about 15 min on each side. The edge got very very smooth. When i finished with it it would cut paper almost as good as a Mora. I still want to polish the edge with a 600 grid paper. How do i know i got a convex edge???
I tried to use the knife same as a uleu (sp??) Worst come to worst i could use that axe for everything. I played with it at work and i love it. I have never had an Axe so sharp before ever. Now i started to polish the head of the axe and it looks good.


Sasha
 
Well, when I was married I knew it was sharp enough when my wife said,
"you've been sharpening your knives again". She could always figure out how many I sharpened by the bald spots on my legs.
 
thats funny Loug. I guess i should ask my Q diffrent way. How do you know when you got a proper convex edge??? Do you use a magnifing glass to check for it?? if you do what do you look for??? I know its sharp and i know that as soon as i get another sandpaper around 600 or more i could get it twice as sharp. But do i have a convex edge??? cant wait to go choping wood. Today at work i used the knife to open boxes and use it for everything you use a knife for. It works great and would be even better if i took the handle off. But maybe i should install a longer handle??

Sasha
 
If it cuts good I wouldn't worry about it, though I'm curious how thin you took it?
 
Hi Buck im not sure how much i did take off. Maybe 1\6 on each side.
Im going to see if i can take a pic and post it. If you lay the axe on its side and put a ruler on top from back to front of the axe head. Thats how i reprofiled it. I took off all i could as long as i didnt file the back of the head. When i finished i used the sand paper to attempt the convex grind. The edge does look very good if i may say so my self. Its very smooth to the touch and feels very sharp. Maybe not as sharp as a kitchen knife but when i cut paper it cut very easy with very little pressure. Im very proud of my self lol. Now i realy want to try my hand at making a knife.

Sasha
 
I gotta warn you, this kind of thing can lead to a nearly unending obsession with getting things as sharp as they can be.

To your original question, if it's convex you will see the slight curve when you look at the edge from the bottom or top of the axe. Regardless, if it cuts like you say, you're definitely on the right track. If it chips when you chop wood with it, it's too thin/acute for the steel/heat-treat; sacrifice a bit of steel and use a slightly more obtuse angle next time you sharpen it. If it binds in the wood, it may be too obtuse, use a more acute angle.
 
thanks GibsonFan I just looked at it and it does have a slight curve to it. Next in line is a very old knife my dad is using to clean fish. After that its one of the kitchen knives. What i realy want to make is a small blade with 3\16 thick spine and 4.5" long and about 5" handle. I like so many diffrent shapes everyone makes. Each one of them is awsome looking. Maybe i should save all the pics and just look at them when i get bored lol.
Cant wait to start making my own first knife.

Sasha
 
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