Tree topping? How sharp CAN it be?

push cut gift wrap tissue paper.

edit: CERN need to deploy RJPS - Richard J's Particle Splitter.
 
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richard j said:
sja2249, i had a customer tell me that he was treetopping hairs with a knife i sharpened (done on 80 grit abrasive). i have a vid of a knife i made cutting free hanging newspaper. http://www.youtube.com/watch?v=I7iDE2EBzBw

i made a knife for a friend here in town and i decided to show him what i call a "novelty edge". i pulled out a moustache hair and proceded to whittle it as if it were a toothpick down to where i was holding it. after that i removed that edge and put on my normal shaving sharp edge.
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WOW!! Did you poke it through the newspaper in the middle to do that? That's amazing! :)

Sam
 
i had to push it through the middle to get it started. i sent that knife out on a private passaround. here is a link to a vid made by unit who had the knife last. http://www.youtube.com/watch?v=8q_eMwRaHYg

when he sent it back, it was still sharp enough to cut but not shave very well. all i had to do to get it shaving sharp again was give it a few passes on the slotted wheel.
 
sja2249 said:
Free standing cigarette paper? I don't understand... Please elaborate?
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Somebody here posted a video along those lines, some time ago. The cigarette paper was folded or rolled to make it stand freely on a tabletop, and the knife was then swung to 'chop' a portion away from the upper end of the folded paper (sort of like swordsmen do with candlesticks, in the movies).

Edit:
Here's the video I mentioned:
[video=youtube;uDOTXr2U0cU]http://www.youtube.com/watch?v=uDOTXr2U0cU[/video]
 
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Well... things are progressing nicely. Please don't think I'm spending hours and hours on these knives... I've probably spent 20 minutes each night for the last 3 nights playing with these knives, and most of that was testing... I'd guess I have close to 30 minutes of stropping total. I probably have an hour or so into each of these knives.

I'm learning that popping a free hanging hair seems to be as much about technique as it is about the sharpness of the blade. I can now pop hanging hairs with both blades pretty reliably no matter how thin the hair. It might take me 6 or 8 attempts, but I'm learning. It seems to matter a lot how I hold the hair and from which end. It also matters a lot how the blade intersects the hair, but I haven't quite gotten that part down yet... which is why it takes me 6-8 tries to pop a hair.

I did try the free hanging newspaper trick, and that went pretty well.

I gave up on my pocket microscope and have been using my 18x loupe. There are some interesting imperfections in the edge, but they are tiny and well polished. If I didn't know better, I'd say it looks like pitting that's been buffed out.

Who would have ever thought that a hairball from the drain could be so useful!? LOL That's my secret source of test hairs...

Sam
 
I took a break from stropping/testing to eat a plum. For fun, I cut a slice off of the plum using only the weight of the knife. As you know, Opinels don't weigh much... Now, this was not a push cut, but using only the weight of the knife ( by holding the very end of the handle between my thumb and index finger ) it took me about six strokes to glide through a ripe plum. I realize this "test" doesn't mean much, but it's amazing to feel the blade just glide through a ripe plum.

I just tried a straight up push cut and the results were not so spectacular. LOL

Sam
 
Next fun test. The weight of the knife ( again, opinels are very light ) was enough to push cut the entire length of a sheet of newspaper.

I apologize for my many posts, but this is both enlightening and highly entertaining. I've never handled knives this sharp so I'm learning all sorts of fun tests for them.

Hopefully, I'm at least entertaining some of you.

Sam
 
i had joezilla send me his emerson a 100 (blade only) to get it reground into a full scandi grind. when i was done i pinched the blade by the pivot hole and held it above a piece of reciept paper from family dollar which is real thin paper. i loosened up my fingers and the blade fell right through the paper as if it were not even there.

here is the link to the thread. http://www.bladeforums.com/forums/showthread.php?p=6774942#post6774942
 
richard j said:
i had joezilla send me his emerson a 100 (blade only) to get it reground into a full scandi grind. when i was done i pinched the blade by the pivot hole and held it above a piece of reciept paper from family dollar which is real thin paper. i loosened up my fingers and the blade fell right through the paper as if it were not even there.

here is the link to the thread. http://www.bladeforums.com/forums/showthread.php?p=6774942#post6774942
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I'm not surprised Richard. I would expect that from your sharpening jobs, in fact. :D
 
many things play into the factor of sharpess . blade thickness for example. i have a swamp rat hrlm with a mirrored edge that you have to angle just right to slice paper. the problem is that the angle on the fixed blade is way too obtuse to do any fine work. can someone let me know about the carbide size on VG-10 because i dant get my damn delica as sharp as the kershaw zing.
 
I did some research on youtube, and I have to say I'm a bit disappointed. I looked up several "hanging hair test" videos... and if what I saw on youtube is a hanging hair test, then my knife already passes. I do plan to refine the edge a little more but it's already doing what I saw those people doing on youtube.

I guess at this point, I'm looking for my next milestone... or millstone, as the case may be. LOL

Sam
 
sja2249 said:
I did some research on youtube, and I have to say I'm a bit disappointed. I looked up several "hanging hair test" videos... and if what I saw on youtube is a hanging hair test, then my knife already passes. I do plan to refine the edge a little more but it's already doing what I saw those people doing on youtube.

I guess at this point, I'm looking for my next milestone... or millstone, as the case may be. LOL

Sam
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Sam - wow dude, how impressive! Yesterday & today I tried to sharpen my bm 940 (s30v) so I can shave with - hmm ouch <= no where as smooth shave as my endura vg10. I've waterstones, diamondstones, natural, ceramic, compound: diamond/cbn/cro from 10um to 0.1um, bare horsebutt & cow leathers . Any pointers for me?
 
bluntcut said:
Sam - wow dude, how impressive! Yesterday & today I tried to sharpen my bm 940 (s30v) so I can shave with - hmm ouch <= no where as smooth shave as my endura vg10. I've waterstones, diamondstones, natural, ceramic, compound: diamond/cbn/cro from 10um to 0.1um, bare horsebutt & cow leathers . Any pointers for me?
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LOL Well, you're already working with a tougher medium than I am. You have an awful lot of blade to grind on and much harder than my blades. These opinels have very thin blades that aren't super hard.

I suspect if you ask anyone else here, I'm doing things all wrong, but I can tell you exactly what I'm doing if you think it will help you.

I rough honed both blades on a DMT Coarse bench stone to set the angle and get a burr on each side. Then I moved to a DMT Fine bench stone and later a DMT Extra Fine bench stone. On those stones, I evened out the sides and chased the burr back and forth until it was gone. When I had it sharp enough to catch hairs and the blade had no detectable burr, I moved to a spyderco UltraFine bench stone for polishing. I finished up by stropping with a sheet of newspaper wrapped around a block of wood. I used Flitz metal polish to polish the edge. For the stones, I used the "take a slice off the stone" method... For stropping, I used a trailing edge method.

I seem to be spending far more time stropping than I expected. I have gone back to the UltraFine stone a couple of times using a trailing edge technique when I found aberrations along the edge, but only very lightly.

I am using a more acute angle for stropping than I did for honing.

You have a lot more equipment and a lot more experience with your gear than I have. I used natural stones exclusively for the first 10+ years. Then I switched to diamond. I've had the ultrafine ceramic stones for a couple of years. This is my first real experimentation with stropping and I really don't have anything suitable. I don't have jeweler's rouge, compound, or even a strop. However, I have to say that newspaper and Flitz is working very well, if a tad slowly. In this case, that might be a GOOD thing. I can definitely see incremental improvement as I go.

Good luck. If there is anything I can do to answer more specific questions, I would love to help out.

Sam
 
bluntcut said:
Sam - wow dude, how impressive! Yesterday & today I tried to sharpen my bm 940 (s30v) so I can shave with - hmm ouch <= no where as smooth shave as my endura vg10. I've waterstones, diamondstones, natural, ceramic, compound: diamond/cbn/cro from 10um to 0.1um, bare horsebutt & cow leathers . Any pointers for me?
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I think I will give you a piece of advice... You have a lot of overlapping equipment that require somewhat different techniques... For the time being, why don't you pick the hone that works the best for you the most often ( waterstone, dimaond, natural, or ceramic ) and practice exclusively with that for a while. When you can get your edge to the point that you can slice hairs off your arm or leg, then go to the strop. Same idea there, use the strop that works best for you with the finest compound that seems to yield noticeable progress... Then post your results and let us know how you did! :)
 
Sam - much appreciated for your advice & details of your technique.

Yeah, grinded my 940 into a zero-saber-grind 15* inclusive was non-trivial, microchip hell broke loose at this acute angle. I slowly micro-bevel angle until stabilize at 28*. My progression as follow - all diamond: 165um, 65um, 25um, 12um, 8um, 6um, 3um, 1um, 0.5um, 0.25um, 0.1um then horsebutt leather. Clean no burr/wireedge after 3um (via 400x usb microscope). My edge can whittle hair after 12um. Lol - my face hates s30v & my sharpening skills :grumpy:

My opinel #9 carbon shaves well after I thinned & took 0.7mm metal from the original apex. I mostly use cbn or diamond charged strop nowaday. Maybe I should retry newspaper for soft-steel knives. I do like to use Cr2O3 HA 0.5um for knives with low or no hard carbides (VC, WC).

edit: my bm 940 is 5 yrs old, perhaps bm didn't perfect s30v HT at that time yet. I knew about s30v grain structure + 2um carbide size which can't really support acute bevel angle - that was a few yrs back, so I thought with all diamond galore maybe I can slice & dice grain+carbide to produce an impossible edge. not!

edit #2: re-honed (yup - lead&trail strokes - heheh for edge durability experiment, not an easy thing) on 0.1um polydiamond surface then 5 minutes of stropped on bare horsebutt leather, my s30v blade now shave stubby with the grain and clean against the hair grain. Made 2 cross grain slices thru a page of newspaper and still shave well. Again, thanks for the advice & inspiring thread.
 
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I have to say that I'm amused that you are asking ME for advice. It sounds like you have more experience with this level of attention as well as a better grip on metallurgy and technique than I do.

I've been honing by hand for 25 years or so, and have only recently even attempted to work an edge until it's fine enough to shave with. For most knives, I stop when the edge reliable grabs hairs, and for some particular knives, I stop when I can easily slice hairs off my forearm.

I guess I fear that for my EDC knives, and edge that fine will not be durable enough.

I'm not sure what the abrasive in Flitz is, but it has been working wonders for me so far. :)

Good luck.

Sam
 
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