I have seen a number of videos where they recommend switching to the leather wheel to remove the final burr. Maybe it is semantics but when I am sharpening knives I make a final very very light pass on the stone wheel to remove the remaining burr. I am sure there is some burr remaining but I cannot feel it. I can definitely feel an increase in sharpness after the leather so it must have removed something.
Can you share your experience on finishing the edge.
Quote from: john.jcb on January 29, 2019, 06:22:29 PM
I have seen a number of videos where they recommend switching to the leather wheel to remove the final burr. Maybe it is semantics but when I am sharpening knives I make a final very very light pass on the stone wheel to remove the remaining burr. I am sure there is some burr remaining but I cannot feel it. I can definitely feel an increase in sharpness after the leather so it must have removed something.
Can you share your experience on finishing the edge.
I do something similar... making a few "light alternating passes" to remove as much burr as possible, (I suggest this a lot)... and can usually use a knife after that if needed. But there's probably a tiny bit of burr left, that the leather wheel (or other method) will finish cleaning off.
In addition, the leather wheel is abrasive, so it will further refine the edge, making it sharper. In fact, my belief is, that if the stone is used to clean off as much burr as possible, the leather wheel will further refine that edge vs. using the leather wheel to remove the burr (which may just tear it off)... leaves an edge not as refined... so either more time is needed on the leather wheel, or you end up with an edge
relatively not as sharp (but still plenty good in most cases).
I also do a few light passes at the end of the session on the fine grit, but before going to the honing wheel, I draw the edge of the blade lightly over the end grain of a piece of wood I have beside the machine. This is easy on the edge, and I find it to be the most effective way of extracting the remains of the burr. I forget where I learned this but I think it is a common technique, and once I tried it I have always done it.
Gord
Quote from: GKC on January 30, 2019, 02:15:04 AM
I also do a few light passes at the end of the session on the fine grit, but before going to the honing wheel, I draw the edge of the blade lightly over the end grain of a piece of wood I have beside the machine. This is easy on the edge, and I find it to be the most effective way of extracting the remains of the burr. I forget where I learned this but I think it is a common technique, and once I tried it I have always done it.
Gord
It is a bad practice (though common) to draw the edge through a wood block, rubber or cork to "rip off" the remnants of the burr. If you do, the metal crud will build up on the front of the slice, and you'll be dragging the rest of the edge through the crud and this, together with breaking off of ledges of material along the edge, will roughen the edge and worsen sharpness.
The following SEM images by courtesy of Todd Simpson show the burr on his ZDP-159 knife in the 1st image, that was then "ripped off" by cutting cross-grain into a piece of redwood in the 2nd image – loss of the sharp edge is obvious:
(http://knifegrinders.com.au/photos/zdp-159burr.jpg)
(http://knifegrinders.com.au/photos/zdp-159burr_cross-grain_cut.jpg)
Wootz,
This is one of the continued excellent contributions you make to sharpening. I wish I'd known many years ago the things I've learned from you.
Kind regards and great respect,
Rich
Wisch I'd have a papper wheel set up.
Wootz rules 8)
Once I get the bevel where I want it, I take one more very light pass on the wheel on the burr side. I try to get the burr even on both sides much like the feather on a straight razor.
I occasionally run into a blade steel that galls very bad. Not sure of the metallurgy, but it might be ferrite "smearing". When this happens, I find myself chasing the burr back and forth at the leather wheel and I have to take a couple alternating strokes with a crock stick to cut the burr at the interface with the apex. These are extremely light strokes, not even the weight of the crock stick. Then finish the leather wheel and then a barber's strop to convex the apex the tiniest bit.
Quote from: B Sharp on February 27, 2019, 12:17:15 AM
Once I get the bevel where I want it, I take one more very light pass on the wheel on the burr side. I try to get the burr even on both sides much like the feather on a straight razor.
I occasionally run into a blade steel that galls very bad. Not sure of the metallurgy, but it might be ferrite "smearing". When this happens, I find myself chasing the burr back and forth at the leather wheel and I have to take a couple alternating strokes with a crock stick to cut the burr at the interface with the apex. These are extremely light strokes, not even the weight of the crock stick. Then finish the leather wheel and then a barber's strop to convex the apex the tiniest bit.
I'm personally not a fan of using a "barber's strop" on a knife, but if you know how, I'm sure the results are great. The rest of your post is pretty much what I do in many cases.
If you drag the knife edge across an old cotton towel or the like the burr will snag threads out of the fabric and you can see them under good light, or with a magnifier if necessary. You can use this technique to determine if you reached the edge while grinding, and you can also use it to see if you've removed the burr. You can save a lot of honing by carefully making that last light pass while sharpening.