nozh2002
BANNED
- Joined
- Jun 9, 2003
- Messages
- 5,736
This is awailable for everyone simple method to measure sharpness at single point of edge.
This does not require complicated equipment or math to calculate results, anybody can do this. Anybody can test blades.
What is needed:
1. Spring scales (I loan one from kitchen) I get used to gramms, but it does not matter.
2. Thick Cotton Tread (I have Caron Grandma's Best 100% mercerized cotton style 295).
3. Scotch tape.
4. Grid paper.
5. Pen.
6. Thread holder - I carve one from wood - only one thing you need to make youself.
What to do.
1. Create test-card - on grid paper write scale numbes vertically (in my case from 10g, 20g, ...200g).
2. Mark point on the edge with pen to test.
3. Stretch and tape thread over thread holder.
4. Put holder on scle and tune scale to show 0.
5. Carefully cut thread by matked edge point slowely pushing blade down and watching scale measures. Remember reading when thread was finaly cut.
6. Put birdy in test card at the row with the measured number.
7. Repeat step 3 to 6 at least 21 times.
8. From the top count 11th birdy on test card - it will be median (you may count from the bottom eather - will be same birdy). This is result of measurement - sharpness. (you may repeat measurment more then 21 then median will be half of this number+1)
Never cheat with single reading, if you are not comfortable with results for some reason - right thing to do increase number of measurement. If you check median is pretty stable with big numbers of tests - more tests better result.
Of course different people probably will have different absolute results, but at least anybody can compate two of his own steels and see which performs better. Or ake to brand new knives out of the box anc compare factory charpness etc...
Thanks, Vassili.
This does not require complicated equipment or math to calculate results, anybody can do this. Anybody can test blades.
What is needed:
1. Spring scales (I loan one from kitchen) I get used to gramms, but it does not matter.
2. Thick Cotton Tread (I have Caron Grandma's Best 100% mercerized cotton style 295).
3. Scotch tape.
4. Grid paper.
5. Pen.
6. Thread holder - I carve one from wood - only one thing you need to make youself.
What to do.
1. Create test-card - on grid paper write scale numbes vertically (in my case from 10g, 20g, ...200g).
2. Mark point on the edge with pen to test.
3. Stretch and tape thread over thread holder.
![thread-01.jpg](/proxy.php?image=http%3A%2F%2Fplayground.sun.com%2F%7Evasya%2Fthread-01.jpg&hash=950e39a4433259b50a61f03d55bce261)
![thread-02.jpg](/proxy.php?image=http%3A%2F%2Fplayground.sun.com%2F%7Evasya%2Fthread-02.jpg&hash=dbc9fb2ecdab27393848cc41d86df3f1)
![thread-03.jpg](/proxy.php?image=http%3A%2F%2Fplayground.sun.com%2F%7Evasya%2Fthread-03.jpg&hash=9d8777aab05be9b9c63dbd09b65a2331)
![thread-04.jpg](/proxy.php?image=http%3A%2F%2Fplayground.sun.com%2F%7Evasya%2Fthread-04.jpg&hash=31a8a53d24a0669f25a34ef3f16cad45)
![thread-05.jpg](/proxy.php?image=http%3A%2F%2Fplayground.sun.com%2F%7Evasya%2Fthread-05.jpg&hash=cd3c8750fc45b7d588332536e5072793)
![thread-06.jpg](/proxy.php?image=http%3A%2F%2Fplayground.sun.com%2F%7Evasya%2Fthread-06.jpg&hash=9549de6ce358b3367e25636c9ae05486)
4. Put holder on scle and tune scale to show 0.
5. Carefully cut thread by matked edge point slowely pushing blade down and watching scale measures. Remember reading when thread was finaly cut.
6. Put birdy in test card at the row with the measured number.
7. Repeat step 3 to 6 at least 21 times.
8. From the top count 11th birdy on test card - it will be median (you may count from the bottom eather - will be same birdy). This is result of measurement - sharpness. (you may repeat measurment more then 21 then median will be half of this number+1)
Never cheat with single reading, if you are not comfortable with results for some reason - right thing to do increase number of measurement. If you check median is pretty stable with big numbers of tests - more tests better result.
Of course different people probably will have different absolute results, but at least anybody can compate two of his own steels and see which performs better. Or ake to brand new knives out of the box anc compare factory charpness etc...
Thanks, Vassili.