Doeswhateveraspidercan wrote: ↑Wed Oct 16, 2019 8:46 amYes a most excellent thread Vivi!
Slaps forehead of coarse only after blowing out my 100 grit WEP PADDLE regrinding S90V Military!
Buy cheap 100 grit stones do not waste good ones!!! Arggghhh
This may be the best post of the day cheap Chinease file!
Affirmative recorded!
First word out the womb - “burr” they just thought he was cold... little did they knowspoonrobot wrote: ↑Wed Oct 16, 2019 1:38 pmHow old are you? We posted around the same time on BF back in the mid/late 2004/5 when you were ostensibly a new hobbyist (as was I) and also a late teenager/early 20s adult.
I should have a 400 grit Atoma waiting for me when I get home from work today!
Back in 2011 I destroyed a folding diamond paddle (Diafold) using it to apex some sorely neglected kitchen knives at a friend’s vacation home. Realizing too late my folly, I bought a 3” long SiC stone at the small town hardware store, glued it to a stick, and used that to apex the dull knives. I now use that improvised paddle for rounding the back edge of bandsaw blades.Doeswhateveraspidercan wrote: ↑Wed Oct 16, 2019 8:46 amYes a most excellent thread Vivi!
Slaps forehead of coarse only after blowing out my 100 grit WEP PADDLE regrinding S90V Military!
Buy cheap 100 grit stones do not waste good ones!!! Arggghhh
This may be the best post of the day cheap Chinease file!
Affirmative recorded!
I had the same experience with Rex 45. The 600 grit edge I put on it did not impress that much. The result of UF rods was much better.basedlarrydavid wrote: ↑Thu Oct 17, 2019 7:25 amAdmittedly, I just sort of scanned the OP and posts after it, but I got the jist I believe.
Personally, I like to consider a bunch of factors in deciding the finish of the edge I achieve — carbide volume, cutting applications, aesthetics, abrasives, hardness, etc.
Let’s take two of my recent favorite steels as examples: Maxamet and Rex 45.
With Rex 45 at ~67 HRC and a low carbide volume (at least compared to 10V-class steels) I’ve found that it really does best with a highly polished edge at a low angle. It takes a very fine edge and due to its high hardness and relative toughness, holds it for a long, long while. I find that using CBN/diamond abrasives and its 3% vanadium content allows for a really nice bite along the edge, even when highly polished. Surprisingly, I’ve also found that it responds to REALLY WELL to stropping (at least with diamond sprays and emulsions). Initially sharpened to 0.1 micron on diamond/CBN (5 micron on the final stone, stropped the rest of the way), I carried my Rex 45 PM2 from roughly mid-July of this year until the end of September, using it daily, including a move where I broke down dozens and dozens of boxes, ties, etc. 2 minutes of stropping at 4, 1, 0.25, and 0.1 micron (a few passes on each) kept it blisteringly, hair-whittling sharp with great aggression.
With Maxamet, I like to take advantage of that huge wealth of carbide and leave the edge coarse. Going too fine with the sharpening would smooth out many of those carbides. Though I have some past experience with it, I haven’t carried or used Maxamet as much as I have Rex 45. However, I recently picked up a Maxamet PM2 and am planning to give it a long run. Just for kicks, here are some microscope pics of the progression:
Metallic bonded CBN at 200/160 micron
100/80 micron
50/40 micron
28/20 micron
Finished with resin-bonded CBN at 20/14 micron
I’ve tried that same progression with lower carbide steels with softer matrices and while it cuts well initially, they did seem to lose their aggression after cutting cardboard/plastic a bit more quickly than I would like. A few days into this Maxamet use and it’s still going very, very strong and refuses to lose that sticky sharpness I love.
So, in sum, I don’t think that there is a one-size-fits-all edge for all steels, geometries, and applications. But in the spirit of this thread, I’ve come to appreciate coarse edges that may not be polished and hair whittling sharp. Love the discussion and insights here!
Steels like S90V for example is jam packed with carbides( along with some of the hardest carbides in the mix), one thing that has to be understood is that the edge of high carnide/high alloy steels breaks down by the teeth chipping on a nano and picoscopic scale. During this breakdown period, the old teeth chip out but new smaller teeth takes its place, like a large glass shard being broken to a smaller piece. By smoothing out the carbides, the teeth will actually break into much smaller or flatter teeth. In other words, you would be speeding up the wear proccess. Where as if you let those carbides hang out more( via coarser finishes) not just at the top of the apex but along the walls of the apex, you end up maximizing the working edge, which is what most stainless /high carbide steels excel in.Pelagic wrote: ↑Thu Oct 17, 2019 4:31 pmWhat exactly is wrong with smoothing out carbides? While I'm largely a coarse grit sharpener, the grit finish you want according to the task you plan on accomplishing while taking the hardness of the matrix into account should far supersede this in my opinion.
S90V is incapable of high hardness though, so it makes sense to keep the edge coarse anyway despite the obvious advantage of making good use of the carbides in general. But what about Maxamet, REX 45, or a steel in between? What exactly is wrong with smoothing out some carbides on REX45? Given I already know a super fine edge will yield less performance, I feel this has less to do with the carbides than many people say. EXCEPT when it comes to working edge. But most of us here aren't so concerned with working edge.A.S.O.K.A wrote: ↑Thu Oct 17, 2019 5:37 pmSteels like S90V for example is jam packed with carbides( along with some of the hardest carbides in the mix), one thing that has to be understood is that the edge of high carnide/high alloy steels breaks down by the teeth chipping on a nano and picoscopic scale. During this breakdown period, the old teeth chip out but new smaller teeth takes its place, like a large glass shard being broken to a smaller piece. By smoothing out the carbides, the teeth will actually break into much smaller or flatter teeth. In other words, you would be speeding up the wear proccess. Where as if you let those carbides hang out more( via coarser finishes) not just at the top of the apex but along the walls of the apex, you end up maximizing the working edge, which is what most stainless /high carbide steels excel in.Pelagic wrote: ↑Thu Oct 17, 2019 4:31 pmWhat exactly is wrong with smoothing out carbides? While I'm largely a coarse grit sharpener, the grit finish you want according to the task you plan on accomplishing while taking the hardness of the matrix into account should far supersede this in my opinion.
In terms of maxamet, its not a stainless/ high carbide, but it is a high carbide/ high alloy as it carries more than 20% in carbides, maxamet is a candidate for a coarse edge. But rex45( a steel I am much more acquainted with) can take a high polish as it is a low carbide/ high alloy steel. Dont get the wrong message, just cause a steel has carbides doesnt mean its bad to polish. But those steels with a carbide level just under or over 20% benefit better with a coarse finishPelagic wrote: ↑Thu Oct 17, 2019 6:11 pmS90V is incapable of high hardness though, so it makes sense to keep the edge coarse anyway despite the obvious advantage of making good use of the carbides in general. But what about Maxamet, REX 45, or a steel in between? What exactly is wrong with smoothing out some carbides on REX45? Given I already know a super fine edge will yield less performance, I feel this has less to do with the carbides than many people say. EXCEPT when it comes to working edge. But most of us here aren't so concerned with working edge.A.S.O.K.A wrote: ↑Thu Oct 17, 2019 5:37 pmSteels like S90V for example is jam packed with carbides( along with some of the hardest carbides in the mix), one thing that has to be understood is that the edge of high carnide/high alloy steels breaks down by the teeth chipping on a nano and picoscopic scale. During this breakdown period, the old teeth chip out but new smaller teeth takes its place, like a large glass shard being broken to a smaller piece. By smoothing out the carbides, the teeth will actually break into much smaller or flatter teeth. In other words, you would be speeding up the wear proccess. Where as if you let those carbides hang out more( via coarser finishes) not just at the top of the apex but along the walls of the apex, you end up maximizing the working edge, which is what most stainless /high carbide steels excel in.Pelagic wrote: ↑Thu Oct 17, 2019 4:31 pmWhat exactly is wrong with smoothing out carbides? While I'm largely a coarse grit sharpener, the grit finish you want according to the task you plan on accomplishing while taking the hardness of the matrix into account should far supersede this in my opinion.
Nothing actually wrong with it. In fact, it is literally dependant on use. I have taken s90v to 3 different stages of sharpening and have found this out: on ultra fine grit( mirror polish), for my use, it will stay abosolutely hair whittling sharp for 2 weeks then quickly drop to work edge and quickly drop to dull. If I put a fine edge on, for my use, it will hold a decent hair whittling edge and a decent working edge. And finally for a coarse edge, for my use, it will hold a working edge like nobodies business. So at the end of the day, your use will dictate what finish is acceptable. FYI, my knife use renders steels like vg10 useless, except in the kitchenPelagic wrote: I'm already aware of that info and that didn't address my question. I probably didn't word it correctly.
