how to sharpen knife

[NormC]

The most important (and often the most difficult) part of sharpening a knife well is the angle. 40% is generally considered the right angle, or 30% if you are doing a back bevel.

I use a Spyderco Sharpmaker. A great product and pretty much foolproof to use.
http://www.spyderco.com/catalog/details.php?product=77

The Lansky sharpener mentioned by Geoff in post 3 achieves a similar result.

[struktcha_man]

Makita sell a stone, 2 sided figure 8 pattern does ok, angle about 45 degrees to the face and your knife is sharp in a minute.


i use a steel in the kitchen and suprisingly a steel puts a nice edge on the blade.

But may not always be handy

depending on the weight of the blade you may need to machine the blade occasionally or the angle will get too dull.


Edit: after rereading I see 45 degrees is too steep, as a few guys have mentioned above 30-40 degrees sounds correct.
Also you don't have to use a figue 8 pattern a sweeping stroke covering the whole edge also works.


cheers

[Tailortaker]

When using an oil stone avoid using any oils to lubriccate it as you will eventually clog it. Use ever watered down detergent (dish wash liquid) or window cleaner ( the blue glass cleaner in spray bottle) These both work well on the stone. Also dont use to much angle, 45 deg is a bit much as you will find that it wont last and you will be back on the stone in no time. The way to keep a good edge is to start with a good knife.
Cheers TT

[freddofrog]

As a uni student I worked in a kebab store and was taught how to use a steel. An oval shaped diamond one if it was really bad or a normal circular one for everyday use.

My parents must have 4-5 blocks of knifes, all of which look terrible due to all the different sharpening tools they have bought over the years.

We just have one block of quality knifes and one steel and mine look as pristine as the day they were bought.

And here's a tip, actually store the blade facing up in the block, rather than down. That way you are not blutting the knife every time you put it in and out of the block. And as it's in the block, storing it upwards isn't a safety issue.

Sharpening stones will work but I have found they will end up scratching the blade of your knife if you aren't careful. No big deal but soon your knives end up looking very average.

And steels are more convenient anyway. They generally sit along side the knifes in the knife block so it's easy to grab it and give it a quick sharpen before you start cutting your veggies or whatever.

Spend the time to learn to use a steel and you'll have perfect knifes. All my knifes, kitchen, fishing, pocket, leatherman etc are all kept sharp with a steel.

[Tailortaker]

As a uni student I worked in a kebab store and was taught how to use a steel. An oval shaped diamond one if it was really bad or a normal circular one for everyday use.

My parents must have 4-5 blocks of knifes, all of which look terrible due to all the different sharpening tools they have bought over the years.

We just have one block of quality knifes and one steel and mine look as pristine as the day they were bought.

And here's a tip, actually store the blade facing up in the block, rather than down. That way you are not blutting the knife every time you put it in and out of the block. And as it's in the block, storing it upwards isn't a safety issue.

Sharpening stones will work but I have found they will end up scratching the blade of your knife if you aren't careful. No big deal but soon your knives end up looking very average.

And steels are more convenient anyway. They generally sit along side the knifes in the knife block so it's easy to grab it and give it a quick sharpen before you start cutting your veggies or whatever.

Spend the time to learn to use a steel and you'll have perfect knifes. All my knifes, kitchen, fishing, pocket, leatherman etc are all kept sharp with a steel.

Stones sharpen knives not steels, steels help maintain an edge

[oldboot]

I have to admit I lost my mojo sharpening knives and am struggling to get it back.

Get me on wood working edge tools & I can get a shaving edge quickly and reliably.

the problem with knoves tha that the edge isnt straight and the blade isnt rigid so they defy the use of jigs.

I think my problem is that I have got pertty good at sharpening the woodwork tools and I am impatient with the knives.

yep it takes time.........I can see why soo many butchers and cooks are soooo very fussy about their knives because once they get past the point of a quick touch up... it becomes a lot of work.

The argued "correct" sharpening angle is 30 deg included or 15 deg per side for meat cutting knives.

On the matter of oil stones....... vegitable oil is not a good idea because it will polermerise in the stone and clog it up rely bad.
some form of thin mineral oil is requred....opinions differ.. I use singer oil or air tool oil..... many profess the use of kerosene or engine oil cut with kerro.
The traditional think is neasfoot oil.... but that stinks

If the stone is badly clogged it can be washed in solvent or boiled in a strong detergent / caustic / washing soda solution.

I have tried quite a number of the pull thru sharpeners and most of them are disgusting butchery devices....they can make a total mess of a knife.....I can get better straight off my grinder.

I did find one at Ikea the other day that seem not half bad....it has a rotating stone and is cheap as chips..... it seems to produce the correct angles and a reasonable edge.......a slightly agressive edge though.
Certainly good enough for the bait knife and the wifes vegie cutters.

On the subject of steels
the traditional steel does not sharpen a knife... but simply burnishes the edge and tends to straighten it.
The diamond steels however do remove significant amounts of material and can be considered sharpeners.

Beware of cheap steels.......like the ones that come in knife sets or baught at the supermarket....... they are a complete waste of time.

I know what i need to do....... practice..... and spend $50pluss on a decent steel

perhaps then I will be able to shave the my arm like I can with my chisels and plane irons.

cheers

[rando]

Long but a good explanation.
http://forums.egullet.org/index.php?showtopic=26036

[freddofrog]

Stones sharpen knives not steels, steels help maintain an edge

You may be correct (or not), but if that is the case then that would mean I have never needed to "sharpen" any of my knifes for the last 10-15 years!

Very recently one of our kitchen knifes mysteriously developed had some minor nicks in it. The wife denied all wrong doing. After a couple of sessions with a standard steel (round, no diamonds) they had all but disappeared.

I guess the point I'm making that even a "normal" steel should be able to take care of most knife issues, including "sharpening" and maintaining an edge and even dealing with mysterious nicks.

[Tailortaker]

You may be correct (or not), but if that is the case then that would mean I have never needed to "sharpen" any of my knifes for the last 10-15 years!

Very recently one of our kitchen knifes mysteriously developed had some minor nicks in it. The wife denied all wrong doing. After a couple of sessions with a standard steel (round, no diamonds) they had all but disappeared.

I guess the point I'm making that even a "normal" steel should be able to take care of most knife issues, including "sharpening" and maintaining an edge and even dealing with mysterious nicks.

Well I hope I'm correct considering I've been a butcher for over 15years !!!
Maybe the fact that you dont use them all day every day is why you dont need to "sharpen"them. cutting the odd potato or tomato would'nt really put much stress on a knife there fore a steel would maintain the edge for a much much longer period of time.

[oldboot]

I think part of the problem here is the concept of "sharpening".

If you take the process as a whole from the forming of the bevel, the dressing the bevel to a sharp edge and then stroping or burnishing the edge to what professionals like butchers would consider sharp... there are a number of processes, within the whole process of sharpening.

you will not form a bevel with a steel....if you are starting with a knife blank or a knife that has been mal treated to the point where you need to start again starting with a grinder or a file is probaly most appropriate.

If you are starting with a knife with a bevel formed at a correct angle but not yet sharp or one that has bee properly blunted... you might get there with a traditional steel but it will take you ages.....A diamond steel will problay get you there... a stone (or two) or a wet grinder is probably the most appropriate.

once the blade is what most people would call sharp....... now this is what a traditional steel is intended for.........you will have a propely formed bevel that you can "feel" on the steel and you are not asking the steel to do more than it is designed for and that is "finishing the job".

If you care for your knives you may never need to go further back in the process than finishing the job again on the steel.
The steel will remove imperfections from previous stages, straighten the edge and tend to harden the edge by burnishing.
If you push its function a little, taking out a small nick or two is reasonable.

If you are a heavy user of knives and perhaps your steel technique is less than perfect...over time the use of the steel will round the edge and cause other irregulartities......at some point the knife will need to be taken back to the grinder or the stone to restore its geometry.

Saying a steel does not sharpen is both right and wrong depending on what you believe the word means.

Different peoples understanding of the word sharpen and sharp can be very different.

To butcher, working a knife on a steel is such a regular thing that it would not be thaught of as sharpening more of a dressing or cleaning process...truly a butcher would problay give more thaught to scratching his nose than a couple of strokes on his steel whilst planning his cuts.

"Sharpening" on the other hand is a serious business hard work and a chore.

cheers

[435_Mark]

I'm very surprised that freddofrog can keep knives sharp with just a steel, especially over 10-15years!
I use a stone with 30wt engine oil, the coarse side first to get the angles right, then the smooth side to put the edge on and then a steel to finish the edge. Takes me 10 minutes per knife unless it is a new knife that I have to put the correct angle on.

I read with interest that you should be careful of oil as it can clog the stone (something I have heard elsewhere as well), however I have been using my fathers sharpening stone for the past 30 years, and he used it for ?? years before that and it has never, ever needed cleaning. As you might imagine it is no longer the stock "block" shape it was when new!

I did like the look of that "water wheel" from Mitre 10. I might have to go and have a look at one of those myself.
Some great info in this thread, well done fellahs.

Cheers,

Mark

[rando]

I'll jump back into the discussion here and share my opinion on lubricants.
The purpose of a stone is to grind away the steel of a knife or tool to shape or sharpen the edge.
In this process both the metal tool and the abrasive particle of the stone break off and create a swarf.
Adding a lubricant of any kind to this swarf creates a slurry that diminishes the ability of the abrasive particles to 'cut' the metal.
If you feel your stone is not cutting well give it a wipe with a cloth, or rinse it in water then wipe it dry.
With the exception of jap waterstones , adding a lubricant to an abrasive process is counterproductive. IMO

[oldboot]

With japanese water stones there is suposed to be a slurry as part of the cutting process they even use a special stone ( a "nagura" I think) to generate the slurry prior to beginning sharpening.......but japanese water stones are different from all others.

With most stones, natural or manufactured the puropse of the fluid is to carry the swarf away and to cool the blade being sharpened.

If you do not use some sort of fluid stones particularly fine ones clog with metal particles quite quickly.

Most of the manufactured stones are very hard in comparison to the metal and only a very small ammout of abrasive is broken or seperated from the stone... that is the point of them.

Apart from specificlay manufactured waterstones........the chioce of water or "oil" is just that a chioce but once you have chosen to use oil there will be quite some problems with using water.

A lot of people use water with their hard manufactured stones because it is convieneint and relativly clean.......note that the water is very low viscosity and does very little lubricating......but it does make a considerbale difference to the performance of the stone.....when using water it is common to dip or sluce the stone periodiclay.........when sharpening knives heat is not going to be a problem because the length of blade is long and the sharpening action is slow.....but if you are sharpening chisels or plane blades particularly using a jig the blade can get uncomfortably hott to handle when sharpening dry....on hand stones it will never get too hot as to cause damage to the blade.

When sharpening edge tools I do the early stages on dry sandpaper..I notice two things... the I often need to stop because the blade is too hot... and I need to brush the paper to remove the spent abrasive and metal swarf.

Once the process gets onto the finer grits I work on oil stones ( hard stones and I happen to use oil with them)....Oil most certaily does improve the sharpening process, the stone actulay cuts more freely and the swarf is floated off in the oil....in the very fine grits the stones are almost impossible to work dry....... my finest stone will give me an edge that will shave my arm ( on a plane or chisel)

The important thing is that the "oil" should be thin....engine oil is a bit too thick...I prefer air tool oil or sewing nachine oil....as i said before many like keroseene.

most of the hard manufactured stones are quite open graded and do not clog redilly........softer stones ( a japanese water stone for example) used with oil will clog very badly if used with oil

Consider that almost all industrial metal cutting process can be improved by the application of a lubricant....it allows the cutting edge to remain sharper for longer and allows the cutting edge to penetrate the metal with less resistance....

A good stone will last much longer when used with a fluid and will continue to cut agressivly for longer.

cheers