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OrgoneConclusion
Blue Fish Group



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Knife sharpening?
#15943394 - 03/13/12 06:55 PM (11 years, 10 months ago) |
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I have some really old and pitted kitchen knives so I bought one these three grade (coarse-150/medium-300/fine-450 grit )diamond sharpening kits. I got the pits out so they were looking pretty good. The edge was smooth, but dull. Much later the edge was still dull and smooth. Got out my Swiss Army pocket knife which was fairly sharp and could cut paper, but also had some pits. Now the blade is smooth, but dull. Good job! 
I know this isn't rocket science so I read 10 articles and watched several U-Tube vids on sharpening knives. I tried light pressure, heavy pressure, circular motion, straight motion, sharpening both sides, sharpening one side, 10 degree angle, 20 degree angle and so on. One method at a time - not all at once. Three hours later my knives as smooth, but dull. Tried different grades of sand paper, a brick, some river stones, ARRRRGGGGGHHHHH! WTF am I missing?
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Prisoner#1
Even Dumber ThanAdvertized!


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the wire edge. when you sharpen a blade you have a little roll of steel that hangs on. that is probably the source of the dull
make use of a strop
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OrgoneConclusion
Blue Fish Group



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Tried stropping with leather and with steel; same-same.
I just used a handheld Smith's sharpenener with the tiny crossed ceramic sharpeners and I can cut again, but it seems really bad for the blades leaving them somewhat jagged; a little more like a serrated rather than a razor.
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Prisoner#1
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are you wetting the diamond stones?
work them as if you're trying to shave the diamonds off.
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OrgoneConclusion
Blue Fish Group



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Tried them dry first, then wet them and tried again. No diff. I have a houseful of butter knives now. Maybe I gave up too soon, but I got 20 year old pits and chips out fairly quickly so I know I was taking off a good amount of metal.
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Prisoner#1
Even Dumber ThanAdvertized!


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bring your stuff to my house and I'll sharpen them up for you, give you a few lessons in dealing with them. it's really an art to do it by hand
some years back someone developed the 'scary sharp' system which works pretty well, it uses 3M micron abrasive papers but standard wet/dry sandpapers can be used, make sure you arent rounding the edge when you sharpen. it's easy to do without even noticing
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OrgoneConclusion
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I am certain I am rounding them. I tried using less pressure and got a better, but still half-assed edge, but nowhere where I want to be. Will check out your video.
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Prisoner#1
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practice on a crap knife when you're doing the secondary bevel, maybe rest it on your thumb while you try and shave the diamonds off your stones
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OrgoneConclusion
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OK, I finally got a decent edge, not professional, buy way better. Some of my knives were so warped and pitted and using cheap steel they just should have been thrown away.
Right or wrong, here is what I did:
1. Focused more on one side than the other to prevent me from rounding the edge.
2. Used small circular motions rather than long sweeps.
3. Lowered the angle to something more like 5 to 8 degrees on one side and almost flat (< 4 degrees?) on the other.
4. Decreased pressure as I progressed.
5. Finished up on 600 grade wet sand paper on a flat surface.
With one heavy knife, I can now cut paper. Not effortlesly like a razor blade, but pretty easily without swiping, hacking or tearing. Compared to what it was, it is plenty sharp enough for normal kitchen duty (and for the occasional night-time intruder).
Thanks for all your input.
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Grapefruit
Freak in the forest


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I don't know why you'd want to use stones for kitchen work, just use round steel, it's way easier and faster whilst still being plenty sharp enough IMO.
-------------------- Little left in the way of energy; or the way of love, yet happy to entertain myself playing mental games with the rest of you freaks until the rivers run backwards. "Chat your fraff Chat your fraff Just chat your fraff Chat your fraff"
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OrgoneConclusion
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Re: Knife sharpening? [Re: Grapefruit] 1
#15959066 - 03/17/12 10:23 AM (11 years, 10 months ago) |
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Steels help to keep an edge, not give a new edge to dull, worn-out and pitted knives.
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Prisoner#1
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Quote:
OrgoneConclusion said: 1. Focused more on one side than the other to prevent me from rounding the edge.
not uncommon but it will cause your knife to cut a little oddly after a bit of sharpening that way
Quote:
2. Used small circular motions rather than long sweeps.
the long stroke is better to maintain an even bevel especially if you use a guide
Quote:
3. Lowered the angle to something more like 5 to 8 degrees on one side and almost flat (< 4 degrees?) on the other.
wonky can be good I guess, your edge will be thin and brittle if your secondary bevel is at 9-12 degrees, you want around 25-30 degrees for decent edge holding and razor sharpness
Quote:
With one heavy knife, I can now cut paper.
would you like to shave with my sword?
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cyanophilus
ectosporium
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use one of those round kitchen honing rods to do the final edge. a stone will get u down to a sharp edge but it will bend over making it feel dull even if its truly sharp.
get a honing rod and do 4 one way 4 the other, 3 one way, 3 the other, down to 1. then go back and forth 1 on each direction til you get the edge straight. to check your work, hold the knife straight up with the blade facing you and run your thumb left and right over the edge of the blade. whichever side feels like its catching your thumb more needs to be honed better.
dont let the bed edge discourage you from knife sharpening, but unless you have had a shit ton of practice then use a honing rod to finish up. I almost guarantee this might be whats wrong.
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trigger
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keep in mind to make the edge disappear, that is there should be no visible edge on the cutting blade.
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Icelander
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I can usually get a good edge even on my filet knife with a diamond stone. You're just old and shaky with bad eyesight and poor skills. Nothing to worry about.
-------------------- "Don't believe everything you think". -Anom. " All that lives was born to die"-Anom. With much wisdom comes much sorrow, The more knowledge, the more grief. Ecclesiastes circa 350 BC
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LunarEclipse
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Re: Knife sharpening? [Re: Icelander]
#16056317 - 04/07/12 10:09 AM (11 years, 9 months ago) |
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Knife Edge
i use stones start coarse go hard using a vigorous circular motion with lots of sharpening oil and cleaned often can slice the ass off a gnat without touching a wing.
-------------------- Anxiety is what you make it.
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Icelander
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Fucking absolutely awesome video!!!!!!
If I could play like that I'd just buy new knives when the old ones got dull.
-------------------- "Don't believe everything you think". -Anom. " All that lives was born to die"-Anom. With much wisdom comes much sorrow, The more knowledge, the more grief. Ecclesiastes circa 350 BC
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LunarEclipse
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Re: Knife sharpening? [Re: Icelander]
#16081195 - 04/12/12 04:41 PM (11 years, 9 months ago) |
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Quote:
Icelander said: Fucking absolutely awesome video!!!!!!
If I could play like that I'd just buy new knives when the old ones got dull.
Knives get dull in the package.
And watch your language young man.
-------------------- Anxiety is what you make it.
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Centerfinger
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Sharpening is determined by the original bevel and edge. Sounds like they are older knives so they could be a convex edge (kinda rounded/ bullet shape), if that is the case then I would start with a flat piece of wood and some 1000 grit sandpaper. You will have to not use much pressure and gently roll up to the knife edge. Start with one side and repeat until you feel a slight burr on the other side, then make a couple of passes on the side with the burr. Build up a burr and then remove it. After the sandpaper move to a leather strop loaded with rubbing compound and do it all again. Look up convex knife sharpening vids to get the technique (knivesshipfree.com has a good video). Flat grinds/edges are different, but will eventually go convex after use and sharpening. I don't sharpen by hand too much anymore, I just stick a micron belt on my knife grinder (not a grinder, but more of a super powered belt sander) that I use to make knives.
Good luck.
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Shroomism
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I used to use a diamond stone but then I got a nice set of professional Japanese water stones and I'll never look back.
Knife sharpening is definitely an art and takes lots of practice to get perfect. Took me a while to get it right where I could get a razor sharp edge.
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