How sharp... does it really matter?
- Thread starter Jack
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Hi. If it didn't matter if a knife was blunt or sharp, why do the manufatcurers bother to sharpen them? A knife or axe needs to be sharp. As sharp as you can make them. I trained as a Butcher, then moved into catering. A chef uses many different knives some thin bladed, some thick bladed, but all of them sharp. Sharpening a knife is not very difficult, or time consuming. Learning how to polish an edge on a sharpening steel is worthwile, (as well as a good party trick when it comes to carving the Christmas turkey) A sharp knife is less likely to slip off the item being worked. But that said, a skilled worker will produce good work, even with a blunt knife, but ask them if they liked using the blunt knife, and i would wager they would say "No"
BlueTrain said:
A push cut, you just push against the work. A saw cut, you saw back and forth. Probably analogous to "slicing" and "chopping". An ax or a woodcarver push cuts. You slice (not chop) vegetables with a saw cut. If you leave an edge with little scratches, like just sharpened on a coarse or medium stone, it will have microscopic "saw teeth" when viewed with a jewelers loupe and will saw cut great. It will dull quickly with a push cut and need periodic aligning of the "teeth" with a knife steel on any cut. If you go to a finer stone and maybe a ceramic and polish the edge you will get a knife that will shave hair and be great for wood carving, will hold an edge for a longer time, but will not saw cut as well.
Does sharpness matter? Of course! 
Do you need a push shaving edge on a knife? Probably not, in fact it may be a lower performer depending on the intended medium to be cut.
However a nice polished edge is a great performer for most tasks and really is a nice thing to have. Is it worth sharpening a knife repeatedly to remove every last dink and chip? Well I don't, but I certainly don't just forget about this sort of thing as a small chip can microfracture and cause a much worse thing like a crack to form if simply left to become a stress point. I at least give the blade a good sharpen and thus greatly reduce the likelyhood that this will happen.
Lack of care for tools is not "bushcrafty" or in some way indicitive of a "real" user rather than a person who looks at loads of knives, collects them and never leaves the armchair. Its just plain lazyness!
Joking aside, always look after your tools, keep the rust at bay on your carbon steel knives and keep them sharp!
A wipe with a bit of flitz and a bit of bog roll will keep the blade protected and rust will go away.
Question I would like to ask is... Rust, does it matter? Why do so many people think a rusty knife is not a problem?
Do you need a push shaving edge on a knife? Probably not, in fact it may be a lower performer depending on the intended medium to be cut.
However a nice polished edge is a great performer for most tasks and really is a nice thing to have. Is it worth sharpening a knife repeatedly to remove every last dink and chip? Well I don't, but I certainly don't just forget about this sort of thing as a small chip can microfracture and cause a much worse thing like a crack to form if simply left to become a stress point. I at least give the blade a good sharpen and thus greatly reduce the likelyhood that this will happen.
Lack of care for tools is not "bushcrafty" or in some way indicitive of a "real" user rather than a person who looks at loads of knives, collects them and never leaves the armchair. Its just plain lazyness!
Joking aside, always look after your tools, keep the rust at bay on your carbon steel knives and keep them sharp!
A wipe with a bit of flitz and a bit of bog roll will keep the blade protected and rust will go away.
Question I would like to ask is... Rust, does it matter? Why do so many people think a rusty knife is not a problem?
Whats the point in carrying a blunt knife, a knife is meant to cut, if it can't do that its dead weight.
Rust is metal cancer, if you leave it it will destroy your knife, given enough time. Also, a momentary lack of concentration and a slip with a rusty knife......Ouch!! I'll let you imagine the consequences of that!
Care and maintenance of a knife shouldn't be a chore, it should take a few minutes to clean and oil after use, so long as you do it every time. Leave it and it will take a lot longer to sort your knife out, and that is when it does become a chore.
Give it a swipe with olive oil impregnated cotton wool after use, you can't go wrong!
Care and maintenance of a knife shouldn't be a chore, it should take a few minutes to clean and oil after use, so long as you do it every time. Leave it and it will take a lot longer to sort your knife out, and that is when it does become a chore.
Give it a swipe with olive oil impregnated cotton wool after use, you can't go wrong!
The General said:Does sharpness matter? Of course!
I certainly don't just forget about this sort of thing as a small chip can microfracture and cause a much worse thing like a crack to form if simply left to become a stress point. I at least give the blade a good sharpen and thus greatly reduce the likelyhood that this will happen.
Which is the best reason to give your blade a bit of a polish, and the reason a properly sharpened knife holds an edge longer. If you go to Old Jimbos site he has some great stuff on giving your knife that first good sharpening and polish and how it then keeps that edge for so much longer. A jewelers loupe and a bit of playing around sharpening will teach you a lot.
http://www.oldjimbo.com/survival/valiant5.html
That link has a pic of an edge which hasn't been aligned or polished, and tells why it might blunt quicker. There are many other good sharpening atricles on the site, great stuff. The other articles are more hands on. In short, sharpen the whole edge on as big a stone (or sandpaper on a flat surface) as possible till you get a burr, or wire edge along the whole edge. Flip it over and do the other side the same way. Then polish with a fine stone, or sandpaper (also large). Finish with buffing compound. The point is to align and straighten the edge, then polish. Then you don't have the nasty spots to grab and break the edge (microscopicly).
http://www.oldjimbo.com/survival/cks.html
http://www.oldjimbo.com/survival/sharps.html
http://www.oldjimbo.com/survival/mora.html
addyb said:
Do you HAVE a Gransfors Bruks??? I do, and it's edge is VERY fine...More than most knives!
davek said:
Try doing the polished edge again and then just ONE or TWO passes on a coarser stone.
I have heard that recommended as giving you a VERY good cut on things like that!
BlueTrain said:
You mean, where you turn the gas on too soon and next thing you know, you do not have any eyelashes???
No, of course not...
spamel said:
What is the differance between getting cut with a rusty knife and one that is not???
I have never understood why it should matter...
I THINK this may come from the fact that a lot of rusty knives are also DIRTY, but I have a lot of things that are VERY clean that also have some rust on them(With an avrage humidity of over 50%, you are GOING to have rust!!!).
spamel said:
What is cotton wool??? I have heard the term a LOT, but have never heard anyone say just WHAT it is...
I believe that sharpness and a correct edge bevel are important - but that's a function of where I live and the damp conditions which we have over most of the year.
There are times when a person can easily smash a few sticks with a rock, then break a small rock and use the edge to scrape some tinder. Much of the time, though, it takes a blade with a decent bevel and a high level of sharpness to make fuzzies thin enough to burn properly. All of my axes, large clearing blades and smaller knives will easily whittle fuzzies for any conditions. I've done lots of experimenting with knives with steeper secondary bevels which I sharpened to easily slice paper or shave hair - but which wouldn't whittle fine enough fuzzies to get a fire going around here.
Probably the thing that's surprised me most since i learned to sharpen properly, is how my blades keep their edges. That applies to everything from axes to tiny knives. Partly this is due to even bevels and straight edges - but partly it's because I have to be careful with the blades, simply for safety.
There are times when a person can easily smash a few sticks with a rock, then break a small rock and use the edge to scrape some tinder. Much of the time, though, it takes a blade with a decent bevel and a high level of sharpness to make fuzzies thin enough to burn properly. All of my axes, large clearing blades and smaller knives will easily whittle fuzzies for any conditions. I've done lots of experimenting with knives with steeper secondary bevels which I sharpened to easily slice paper or shave hair - but which wouldn't whittle fine enough fuzzies to get a fire going around here.
Probably the thing that's surprised me most since i learned to sharpen properly, is how my blades keep their edges. That applies to everything from axes to tiny knives. Partly this is due to even bevels and straight edges - but partly it's because I have to be careful with the blades, simply for safety.
davek said:
So that's the difference! Well, some of it went over my head. However, on the knives I use in the kitchen I never use more than a sharpening steel or whatever you call it. I don't cut anything especially hard in the kitchen. But I've already told you about my wife and her habits, which are another story. But we use different knives and so it doesn't matter.
I cannot claim to have ever examined any knife blade microscopically, only tested them on ordinary things like tomatoes, carrots, potatoes. By the way, I chop vegetables all the time--well, sometimes--with a French chef's knive using a rocking motion. But clearly the sharp knive is the one to use. All my kitchen knives and all but one outdoor utility knife are stainless.
Speaking of rust, on the other hand, objects that are constantly used but made of carbon steel usually take on a bright finish, depending on the steel, and sometimes more of a brown finish. Think of army gear that is constantly used under rough conditions and all the edges will take on a shine. For what it's worth, I've never seen a particularly rusty 65 year old bolt-action army rifle, which is not to say that many did not end up as junk. I guess what I'm trying to say is that if it is used, the rust won't become a problem.
jamesraykenney said:
Whenever I cut myself as a kid and ended up in A&E they always asked if I'd cut myself on something rusty and if I'd had a tetanus injection. Then they always gave me a booster shot anyway.
For this reason I'd always thought rust was a carrier of tetanus. Well it's not. Animal urine and faeces are and the bacteria can be found in soil. If you cut yourself it allows the tetanus bacteria to enter your bloodstream. So if you work in a stable or cow shed and cut yourself on a rusty nail there is a high chance of infection, whereas if you cut yourself on a rusty knife that is otherwise clean then there is almost no chance of tetanus infection. You would also be just as likely to be infected by a non-rusty nail in the same stable.
However, you might still get an infected wound from a rusty blade the same as you might from any other wound. I heal up pretty quick and almost never get an infected wound but other people don't and need to make sure they disinfect any wounds immediately.
