Thread: Knife Sharpening

I am trained in the knife sharpening skills for boning meat so the style may differ from what you are used to. Just briefly, the "steel" should be a very hard high carbon smooth magnetised form of steel. The profile is a matter of personal choice. It must be smooth or you are going to wreck the carefully prepared edge.
To prepare the edge, first ensure that the blade is flat with NO secondary bevel. This may require hours of backbreaking work on a coarse stone. Then go to the smooth 1000 grit finishing stone, raise the edge 7 degrees and working from ferrel end to tip and edge first carefully put a micro-bevel on the edge. 3-4 strokes should do it if the sides of the knife are indeed flat. Dont work the knife backwards and forwards, it should be one smooth controlled pass over the stone stopping with the tip ON the stone dont run over the edge. OK 3 passes later check for a wire edge. If there is one, one stroke in each direction at the 7 degrees until it is gone. Clean the stone frequently to ensure the bits of wire edge dont chip the new edge. Then steel it. 7 degrees and if you arnt used to steeling a knife pretend you are sharpening a pencil and do it away from you .
Fewer accidental cuts this way.
Each time you sharpen, flatten the sides, it sounds like a chore but once the initial work is done it is easy to maintain.
We did this up to 8 times a day inthe boning shed and the knives cut very very well.
We never used a finer stone because the knife has to have a slight roughness to the edge in order to çatch on the meat or veges. If the edge is too smooth it will not cut as well. Bizarre but true. Nobody ever used the soft razor stones of 4000 or 6000 grit, I tried once but the knives did not cut well.
I hope this is of some use.

Originally Posted by hybridfiat

We never used a finer stone because the knife has to have a slight roughness to the edge in order to çatch on the meat or veges. If the edge is too smooth it will not cut as well. Bizarre but true. Nobody ever used the soft razor stones of 4000 or 6000 grit, I tried once but the knives did not cut well.

Hybridfiat made a good point here. This is also well understood by the Japanese blade masters, but in their case they use natural stones to achieve this. Natural waterstones are never completely homogeneous, being a mix of grit sizes that create micro serrations along the edge. But, being more expensive than man-made waterstones, and also harder and slower to use, would not be practical for a boning room.

However, one of the benefits of natural finishing waterstones is that they will create this serration effect right up into the finer grit sizes, starting at about #12,000 and going up from there.

Of course, the big difference between the Japanese blade edge steel and western blades is the hardness. Some of the edges on my handmade Japanese knives are as high as C65. Far too hard to be cutting bone or steeling, but once properly sharpened they retain their super sharp edge for ages. One knife that was fully sharpened when it arrived from Japan (with Yasuki blue steel edge) was still thinly slicing ripe tomatoes in our kitchen nine months later after being used every day for slicing vegetables and meat. I say 'slicing' and not 'chopping'. These high C blades are too hard for chopping, they are designed for slicing. Think of the serrations on your bread knife and how it slices bread rather than chopping it. The bread knife is a gross example of edge serration, but the principle is the same.

I don't own a steel, just a swag of waterstones which I get out about every 3 or 4 months and spend an hour or two bringing the edges back up to super sharp. My knives are always very sharp and visitors have to be warned as they are mostly not used to sharp knives. The down side of this is my family and friends now arrive with their knives to be sharpened... That's when the I need the diamond stone to reconstruct the edge profile ready for the waterstones.

Neil

Aye, knife sharpening is an art of it's own, especially for stainless boning knifes in industrial food processing. When I was a student, during summer holidays I worked at fish farm. I still occasionally help my father-in-law as an assisting butcher in his pig farm. The requirement of hygiene for food processing tools has attached to me pretty permanently, and that's why I have in our home kitchen only plastic handled Swibos, F Dicks and Victorinox stainless knifes of different sizes and styles, just because I can throw them in the dishwashing machine after use.

Victorinox and F Dick seems to use 420 steels, tempered somewhere around 54-58 Rc. Swibo is quite a much of similar kind. These not so hard tempered stainless edges can be treated by steeling without severe edge chipping after a quite coarse grit stone. Steeling does not remove the coarse stone induced microserration, it only bends and aligns the tips of the serration "teeth" in a single line. That kind of edge works very well for cutting soft food tissues.

I have a swedish Dianova Lapstone diamond sharpener for my kitchen knifes. It is two-sided, 60 and 30 micron surfaces. It can be cleaned with a dishwashing soap and water. Does not rust or erode. The steeling rod needs indeed to be very hard and polished. I have an oval steel rod, where larger radius side works quite well in aligning the edge, and it is not that heavy to use, either.

Kippis,

sumu

Steeling does not remove the coarse stone induced microserration, it only bends and aligns the tips of the serration "teeth" in a single line

.
IThe steeling rod needs indeed to be very hard and polished. I have an oval steel rod, where larger radius side works quite well in aligning the edge,
Kippis,

sumu[/quote]

And hybrid with his magntised steel.

Spot on.

A steel steel stops a blade from getting blunt as quick and removes any fragile bits of the edge so they don't end up in your food.

I have seen fanaticial people blunten a new steel to completely smooth on rock /stone or emery paper and then use acid to etch some very very fine cutting edges/serrations onto the smooth steel.


My 2 bobs worth and I need to drive this a bit better next time.
Peter

As the only one in the family with any sense about a sharp edge I am constantly out with the Victorinox steel on the Victorinox knives and a couple of el cheapo others.

SWMBO likes the tempered glass cutting board

I use the brush box slab

They stick em in the dishwasher - I wash and put in the knife block otherwise they will rattle around on or in the sink

Very rarely do I have to take a knife to the workshop for serious honing - really only when the blade profile needs to be restored. The traditional steel is all I need to keep an edge to do the job at hand. If you need more than that - change your butcher!!!

The exception is probably the bread knife - use a stone to put the tips back on that the glass board removes

Have not tried ceramic or diamond steels and if anyone can tell me why and how much better they might be I'll listen but a good quality steel for home kitchen use seems more than adequate to me.

SWMBO now uses a steak knife to cut up stuff as the sharp bits scare and damage her

Hate to use a saw in her workshop

Just my experience

When I first started sharpening my kitchen knives I found it hard to do freehand with a stone.

I made a jig to point me in the right direction.

I detailed it here:

"http://www.knifeforums.com/forums/showtopic.php?tid/807025/"

On well hardened steels in the 60C+ range, the typical textured honing steels will chip out the edge-they murder a good Japanese knife in moments. A diamond won't tear and the rate of steel consumption is proportionate to the physical force applied. But, saying that, I never use anything but an 8000 waterstone or translucent or Black Arkansas on a Japanese knife. The steel in your new knives is very good and very tough. I recommend gentle use of diamond stick, and a hard Arkansas for edge configuration.Just Ole' Lefty

Originally Posted by J.E. Mike Tobey

..the typical textured honing steels will chip out the edge-they murder a good Japanese knife in moments...

I'm with Tobey on this one. Grandfather's steel is knocking around in the back of a drawer somewhere with his old Sheffield Sundaty roast carving knives, where I think they belong together...

It's waterstones for the C60+ hand-forged Japanese knives (and diamond if a lot of metal removal is needed) in my kitchen and wood workshop.

Neil

Leonard Lee's book on Sharpening has a chapter of knives:

Bevel angle is also a key consideration.

...

My SO used slicing knives for chopping, levering and generally butchering; wouldn't take advice so I got my own set. Use a pair of ceramic V wheels for freshening the edge, and now have a wet grinder to reset the bevel from time to time. Used to do this freehand on an 80 grit Alox wheel but that consumed too much steel.