Is there an art to sharpening

ShipsWoofy

ShipsWoofy

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My Swiss army knife, which goes everywhere with me, fab tool! Has a problem, I blunted the main blade cutting bubble wrap, well, cutting it on the floor actually did the damage.

I have tried a couple of times to sharpen it back but never quite get there, nor maintain any sharpness I had.

Tools available,

1 double sided sharpening stone
1 kitchen knife sharpener (the type that looks like 6 wheels)
1 dremel and lots of attachments including paste and polishers
1 angle grinder (though I think this would be over kill)
1 blow torch (do I need to harden)
lots of other stuff, but the above are surely more than enough.

So come on chaps, what is the trick to sharpening and keeping the edge smooth and lasting as long as it did originally before I blunted it?

Thanks in advance.

J
 
The sharpening stone should be able to get it back to it's original sharpness. The trick is to get the right angle against the stone, and you can get little attachments you clip onto the back of the blade to ensure you get it right.

I take all my knives to the local kitchenware shop where they are happy to sharpen them, and they come back perfect. Only costs a pound or two per blade.
 
My wife once asked the butcher how best to sharpen knives and he suggested a kitchen knife sharpener [the kind with a number of hardened metal wheels]. I've used one of those for many years now - very quick and effective. I make sure that I flick the wheels around after every sharpening stroke to avoid any flat spots developing.
 
Not a great expert, but my dad showed me how to sharpen chisels etc. You can use a stone or dremel down one side, make the edge itself to maximum 60 degrees (so angle the piece or sharperner max 30 degrees) and do most of the work on ONE side only, to throw up the burr on the ther side. Then with only one or two strokes - run the blade on the other side. And once back on the other side, and once more gently on the other side. In the limit, the sharpness is determined by your handling of that burred-up metal from one side to the other and up to the middle. Once a blade is sharpened, it goes blunt incredibly quickly - just notice the difference between a brand new saw and one you've sawn a few lumps of plywood. A quick sharpen frequently is what's needed, not getting a man in once a year, imho...
 
I have been told by both a chippy and a butcher that the reason most blades blunt quickly is the angle they are sharpened. Both said they should not be too acute. It seems to work for me.
Allan
 
Well that's the problem really, I had managed to get a nice sharp edge a couple of months ago but now it has gone back to an almost table knife edge.

Before I blunted the blade the edge had maintained it's sharp for a few years of owning the knife. Is it a case of once you have to sharpen it at home you have to keep at it.

How does the manufacturer (victorinox) manage to keep them sharp for years and I can only manage months?

Is it that I am making the blade too thin, trying too hard to get it silly sharp and so weakening it?

It is a right pain having to borrow SWMBO's Gerber knife when I have a knife in my pocket ;(
 
Keeping a knife sharp is one of those black arts that is impossible until you have the right knack (and the left one too). However, I learned in a slaughter house and for the last twenty years all I have ever used for kitchen knives, pen knives, sheath knife, is a butchers steel. One strokes the knife gently back and forth alternating the side of the knife touching the steel. The secret is maintaining the same angle between knife and steel time after time. It only took me about five years to get the technique correct, then I found a better job!!!
 
Do not grind the blade, this will heat it and draw the temper. Any knife is best sharpened with a fine oilstone, or a water lubricated stone. For the best sharp edge finish with a water lubricated fine Arkansas stone. I have a kit from Smiths in the USA which has the fine oilstone, special thin oil, a plastic wedge to demonstrate the correct angle, and the Arkansas stone to finish the job. Second best in my view are diamond laps, which are good in medium grades to re-shape the edge, but need to be superfine to give an edge as keen as the Arkansas stone. I think I got my kit from Axminster Tools.
 
I used to use an Arkansas stone in work to polish mounting faces on RADAR panels. From what I remember they are very expensive?

I remember spending a lot of my time with it up to my nose, they have a rather nice smell?? But then, I love the smell of OM12 so what do I know!
 
Go to your local Ironmongers or fishing tackle store and buy a diamond sharpener. A few light licks with this will soon have the blade as sharp as new. The steel used on a Victorinox Swiss Army Knife, is of excellent quality and should hold a good edge for ages and when sharpened properly, will shave the hairs of your arm with no trouble at all.

url=http://www.tacklebargains.co.uk/acatalog/Online_Catalogue_Hook_and_Knife_Sharpeners_169.html]Diamond Sharpeners[/url]

Instructions for use usually included.
 
The Tri Hone system from the same source would be better. The point is that the pocket stone will be a medium fine grade, whereas what you need for a really good edge is a very fine stone. I have one so fine that if you run your finger over it you can barely feel any abrasion, and that is the one you need to finish the edge.
 
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Well that's the problem really, I had managed to get a nice sharp edge a couple of months ago but now it has gone back to an almost table knife edge.

Before I blunted the blade the edge had maintained it's sharp for a few years of owning the knife. Is it a case of once you have to sharpen it at home you have to keep at it.

How does the manufacturer (victorinox) manage to keep them sharp for years and I can only manage months?

Is it that I am making the blade too thin, trying too hard to get it silly sharp and so weakening it?

It is a right pain having to borrow SWMBO's Gerber knife when I have a knife in my pocket ;(

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When the blade is new it has chrome on the cutting surface which is harder than the steel, once this has worn off the blade will blunt quicker.
 
For a really sharp cut I finish chisels off with solvol autosol on a piece of glass. (Yes I thought it was a joke at first when shown to me by an old cabinet maker) I`ve used it ever since.
 
I'm with Norman_E. I have a VERY fine oilstone & use it with a little water. A few draws across the stone (moving the knife with the stone held on a flat surface) pulling the knife towards me with the blade pointing away. When you can feel the burr on the top edge, two strokes on the opposite side of the blade will remove them. Alternatively use a leather razor strop on alternate sides of the blade & the burr will drop off. My old woodwork teacher used to use the palm of his hand as a strop - but you have to be confident you are not going to be distracted!

A freshly done knife (of almost any sort!) should be able to slice cooked meat wafer thin.
Knives are difficult to store without the edge being lost. If an edge is vital, always sharpen first. It should cut like a new Stanley knife if done properly. Blunt knives can be more dangerous than sharp ones as you will try to use more pressure and it may then slip . . . & flesh cuts quite easily!!
 
Thanks all, I have just taken my time with a fine stone and a bit of 3 in 1, I have never heard of using water on them?

The blades I did the little one too now easily slice through paper, I don't think she would thank me if I started cutting meat with this knife..

As for running your finger over the blade, well, I am still sporting a nice deep cut on the top of my thumb after trying to see if my plane blade was sharp enough to take a bit off the back door as I get fed up in winter having to kick it!

I did not think about the chrome, that does make perfect sense. Will have to get a stone for the boat, I might get an arkanas this time to compliment the oil stone I have.

Why do gypsies never come around and sharpen knives and garden shears any more, is it just not as lucrative as tarmac?
 
Most people use oil on sharpening stones, because water can rust steel and has to be dried off afterwards. I use oil on coarse stones. The downside of oil is that dirt sticks to it, and you must therefore keep your oilstones boxed when not in use. In addition metal particles can clog the stone which may have to be washed in paraffin to remove them. With very fine stones like the hard Arkansas stone water is better than oil. These stones cut faster with water and do not get clogged with fine metal particles because you can wash them in water after each use. What you cannot do is use oil, then change over to water, you must use water from the outset with them.
 
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.... all I have ever used for kitchen knives, pen knives, sheath knife, is a butchers steel.

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I believe the point about using a "butchers steel" is that it burnishes the edge rather than removing material. It also has the effect of work-hardening the edge presumably making the edge last longer. This is a very effective way of maintaining a sharp edge rather than creating it - regular maintenance rather than reaching a repair situation as previously suggested by someone else is probably the answer.
 
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