(10-04-2018, 02:12 AM)Jan Wrote:(10-03-2018, 12:08 PM)SteveG Wrote:(10-03-2018, 09:11 AM)Jan Wrote: I enjoy the fruitful discussion in this thread. Every post may be the missing stone in the mosaic how to proceed efficiently when deburring an edge.
It's a temptation to find universal rule how to sharpen without a burr. In my understanding the burr formation process is not fully understood yet. It depends among others on physical properties of sharpened blade. The most important property is the ductility/brittleness of the blade. Ductile materials form large positive burrs while brittle materials form smaller negative burrs by break out mechanism.
Nevertheless it is surely worth to look for a simple approach how to minimise the burr which is to some degree unavoidable phenomenon of sharpening.
Jan
I never thought of "negative burrs" as a way of expressing that concept - nice!
Two other things worth noting (maybe, I'm not the most qualified observer here):
- Most of the people I've heard of doing this method are using very acute sharpening angles, so even their high-angle passes are often lower than what I use regularly (20dps).
- A point that's often emphasized is that the stone needs to cut. Sharp, fresh grit, otherwise you're just smearing/damaging the metal. I've often wondered with edge-leading if that doesn't lead to the "negative burr" you referred to. For me, as you alluded to, different steels respond dramatically to different stones.
Steve G, I have not invented the terms "positive and negative burrs", I saw it used in papers concerning machining.
Both, positive and negative burr can develop in an edge-trailing regime depending on ductility/brittleness of the sharpened blade. The attached picture schematically explains the burr formation process.
Jan
I've read some of the academic/research papers I could buy or get access to, but don't recall seeing this illustration before, and it's a very informative depiction. Could you cite the reference (if it's not much trouble)? I think it's from "Burrs - Analysis, Control and Removal: Proceedings of the CIRP International Conference on Burrs, 2nd-3rd April, 2009" (which is out of my price range - hoping there might be a stand-alone paper). EDIT: Shoot, I found the reference AFTER I posted this message - sorry for the misdirect. For reference, I found it here: https://www.researchgate.net/publication...al_cutting