Getting a burr
- This topic has 12 replies, 3 voices, and was last updated 04/18/2020 at 5:39 pm by
.
-
So for me this works: I raise a full burr only once with whatever grit I start with (100 on a full up, 400 on a touch up). I remove the burr with a single very light edge leading pass on the burr side. I then go thru the grit progressions alternating at 25 passes per side (sometimes switching edge lead/trail). I use the 3 finger sharpness test as well as upside down finger nail scrape to check how it’s going. The sound made during passes also helps.
A couple other thoughts…when I raise the full burr I can definitely feel it tip to toe using my finger swiping vertically. After removal it’s definitely gone. When going thru my progressions I never can feel a burr. Also, to raise the first burr I need to do 25-50 passes (non alternating) on each side scrubbing all the way.
It occurs to me that to raise a burr at each grit would require alot of passes after you have reached the apex inorder for the “steel” to bend over in order to verify that you raised a burr. And if you are doing it with alternate passes you may snap it off and never actually feel it. My approach takes 10 mins on touch up and 15-30+ mins on reprofile.
Comments would be appreciated.
I don’t share that experience. For me the burr forms quickly and easily with little effort, once the initial burr is created with my beginning coarsest grit. As I progress through the finer and finer grits the burr forms quicker and easier with each subsequent finer grit.
I don’t keep a track of my time spent sharpening. There is no reason for me to do this. Knife sharpening is a hobby that I enjoy. I’m done when I’ve achieved the results I’m looking for. Also, I don’t count strokes. Again, sharpening is results driven. I’m move on when it feels and looks ready. I’m done when it looks and feels done.
Marc
(MarcH's Rack-Its)Just to be clear…nobody is right or wrong. The beauty of it is our techniques can be totally different while each of us can have similar results. Take what you like from each of us and put it together how you like it and it works best for you.
As long as you’re angles are consistent and your sharpening strokes are apexing the knife edge, a sharp edge will follow. How sharp your edge is is dependent on how well you do what you’re doing.
Marc
(MarcH's Rack-Its)So just wondering MarcH, and I ask this out of respect and because I would like to try your technique and see if I can detect any differences:
When you are raising the burr at each grit are you doing alternate strokes per side or just a bunch on one side and then a bunch on the other side ?
Any rough idea of strokes or time that you spend at each grit ?
Do you remove the burr and then raise another one at the next grit ?
Do you feel each new burr with a vertical finger swipe and do they feel different (ie. softer for lack of a better term) as you raise them each time ? I would expect a burr made with the 3000 grit diamond would be quite soft vs. the one raised with 100 grit which is pretty hefty and reminds me of burrs raised on purpose for wood scrapers.
1 user thanked author for this post.
Terry, you can definitely feel a burr raised with 100 grit with an edge trailing vertical finger swipe on the side the burr bends toward. To me it is much more definitive than reflections or my 250X cheapo scope. You can can do this and verify you have it across the entire edge. The burr doesn’t come all at once, the burr is formed in parts of the edge first but keep at it and you will have one tip to toe. I do not go further until I have that. You can also flip the full burr to the other side if you want to feel it there too. After a single edge leading swipe on the burr side with 200 grit the burr is gone and never returns with 25 alternating strokes per side thru the progression.
I asked MarcH about his technique because I wonder if I am leaving “sharpness on the table” using my technique.
I rely on visual inspection with a USB microscope in conjunction with finger feel for the burr and edge sharpness. I also test each grit edge for sharpening progression by pulling a piece of newspaper down across the clamped knives edges. I’m looking for the change, that is the improvement, in ease of cutting the paper and the sound made while cutting the paper with each grit compared with the next finer grit.
I start each grit one sided with scrubbing strokes done alternating by switching back and forth from side to side to keep the amount of effort and steel removal similar. There’s a balance between the formation of the burr then removing it when you switch to the other side of the knife edge. As you get further along in the progress of profiling the opposite side bevels and apexing the edges, with each subsequent grit, the burr is formed and quickly removed all along the length of the blade. When I see and feel the burr has formed I know that side and that portion of the edge is profiled how I want it. Then I move my attention to the other portions of the blade till the entire length on both sides reached this point; burr on then burr off. So the burr is really just an indicator of my progress and I don’t leave it in place for very long.
Once I’m satisfied my bevels are profiled, that is angled and shaped, flat and even sized along both sides of the entire knives lengths with the scrubbing strokes, then I switch to alternating side (left-right-left-right) edge leading (down and onto) strokes. Again, I use the USB microscope and finger feels to monitor my sharpness progress.
To expand on the explanation of my technique, I work any knives I’m sharpening in portions. Only working a portion of the length at any time. The size or actually the length of the portion is determined by what is working best for that particular knife and the shape of the knife edge. I keep the amount work balanced by the time I spend on the portion without actually counting the strokes. It’s more by the monitoring my back and forth or down that portion of the edge then back up, a few times, then I switch to the other side and repeat it, similarly. I blend each portion together with overlapping strokes as I do the next portion until the entire length on both sides is done to my liking.
When I’ve done the scrubbing first followed by the edge leading strokes till I’m satisfied with the appearance and the feel, I move on to the next finer grit and repeat. The improvement I feel and hear with the pull down paper cut test with each grit helps me monitor my progress.
I’m visually inspecting for in-line, parallel, scratch patterns with these scratches of similar width and similar depth corresponding with the grit being used. When the appearance is consistent and I have done my two stroke technique I move on up a fine grit and repeat.
Each finer grit is quicker and easier to complete because they’re really just refining the profile created with the first grit. First time sharpening are more laborious and time consuming and are done with a coarser beginning grit. Touch-ups are easier, quicker and can be started with a finer beginning grit depending on the level of edge wear and damage.
My results are entirely dependent on the quality of the beginning profiling done with the starting grit. Finished results are dependent on the consistency and attention to detail from each grit along the entire process. Poor quality results from earlier grits can stay with you through the entire sharpening process. They will probably more so effect the final appearance then the final sharpness. The amount of time I spend, and the appearance of the results of each grit will determine the quality of the final polish. The trick is to find the balance between sharpness, durability and mirrored appearance that fits the needs of that particular knife and it’s purpose and duty.
Marc
(MarcH's Rack-Its)
- You must be logged in to reply to this topic.