Cutting Dyneema & Spectra

This is just a quick thought for all those people who have tried to cut this stuff with a knife or a set of cutters. Whatever you use it seems to be very hard to cut. Even an apparently sharp knife often leaves a ratty end after you have sawed away at it. A hot knife slices right through it but the result is pretty ordinary and the material doesn't really melt in the way that something like nylon does.

In frustration the other day I reached over and picked up a big Japanese Deba. For those unfamiliar with a Deba it is the Japanese knife used for filleting fish. It looks nothing like a western filleting knife: instead it's heavy - the blade is often 3-5mm thick, sharpened only on one side and very broad. Like most Japanese knives the steel is harder than western knives and it is sharpened at a finer angle. Having said that, Deba traditionally have softer steel than most other Japanese knives in order to avoid chips when hitting small fish bones.

The Deba in question

The Deba I use is a modified Deba - the steel is slightly stainless rather than simple high carbon and it has a western style handle. Nevertheless it takes a seriously wicked edge with a few swipes on a water stone. This knife is so sharp that it's not until you see the blood that you realise you have cut yourself. It is the sharpest knife in the house and I have several other very sharp Japanese knives.

Back to the Dyneema. The stuff I wanted to cut was both heat set and "normal". I put it on a board and the Deba just glided through it. I was pretty stunned. I had expected that it might help a bit, but this was a revelation...it just sliced straight through the material, no deformation, no ratty ends, it just did it.

The problem is that you don't want to be carrying around 420g of knife with an 18cm blade and 32cm in overall length - that's nearly a pound of knife and over a foot long in the old measurements.

I think there are options however, a Ko Deba is a smaller version of this knife and it comes with blade lengths of around 8 or 9 cm - so half the length of mine. An example is here.

This might become an essential rigging tool. However you'll also need to learn how to sharpen a single sided blade and you'll need some decent sharpening stones.

Perhaps a good starting point for understanding this knife is to go to Watanabe Blade and have a look at some. It's also worth having a look around that site at other knives. Please be aware that Watanabe San says he's very busy at the moment! Just for reference Watanabe's small deba have a blade thickness of 3.2mm whilst my large Deba has a blade thickness of 5mm.

Two final things to be aware of: most Japanese traditional knives are high carbon steel and therefore they will rust easily unless cared for - camellia oil is your friend! The other point is that the steel is hard and therefore more brittle than the knives you may be used to. If you maltreat these knives they will chip and it is a sad thing to see. Some of the knives have a soft iron back forged to a hard steel cutting edge. These are stronger knives but the cutting edge is still hard and therefore prone to chipping if maltreated. I'm not sure they will take being hit repeatedly with a marlin spike or mallet!

To Cut is to Cook

At least that's what the Japanese say. In truth there's not much you'd want to cook that doesn't require cutting something at some point. Cooking can be pretty humdrum, same old thing, day after day. But you can add some passion to it. The process of cooking can excite you just as much as the eating of the food. That's where knives come in.
You can't cook good food without good knives because you can't cut cleanly, you end up doing a clumsy job of breaking food down and you cut yourself. What's the first stage of digestion in that stir fry your cooking? It's the cuts you made when you chopped the capsicum, garlic, onion, ginger and whatever else you tossed in. When that food is well cut and conforms to the picture in your mind of how it should look then it makes you feel good as you toss it around in the wok.
I grew up with crappy knives - a couple of stamped knives from a couple of different makers that wouldn't stay sharp. Then I made the (repeated) mistake of letting "knife sharpeners" - the people that is who claim to do this for a living - attempt to sharpen them. They made a crap job, I got frustrated and I cut my fingers. Finally having nearly amputated my left thumb I decided enough is enough.
Just on that subject. Ask anyone over about 30 to hold out both hands. You can immediately tell their "handedness" by the scars on their index finger. I've got 7 old and visible scars on my left index finger and a similar number on my left thumb - all inflicted by my dominant right hand wielding something sharp (or not so sharp). My right thumb and index finger are virtually scar free.
So onto the hunt for decent knives. I wanted something that had a good shape, felt good in my hands and would take and keep a really good edge. And I wanted to sharpen them for myself, at home, in my kitchen - no "knife sharpeners" ever again.
Japanese knives were where my head took me. The Japanese say you only need 3 knives in the kitchen and they should all be single bevel knives. Japanese knives are traditionally sharpened on only one side which means they are handed. If the sharpened bevel is on the right side as you hold the knife then it's for a right hander and vice versa. Many modern interpretations like the Global knives are sharpened on both sides just like a western knife. The other key difference is that Japanese knives use very hard steel so the angle at which they are sharpened can be much lower (and therefore sharper) without the edge folding as it would on a "softer" western knife.
So to the three required knives:
A Deba - this is a big heavy knife with a blade around 190mm long (up to 270mm) and a spine about 5mm thick. It's a big muscular sort of knife and it's used mainly for filleting whole fish. In the west we use slim flexible knives to fillet fish. The Deba isn't thin and it isn't flexible - quite the reverse - but it fillets fish superbly. The bevel is always laid against the bone and the knife held in a choke grip with the forefinger along the spine. This gives amazing feel - you can feel the knife ticking over the bones and the fillets come off very cleanly and with no waste left on the bones. It's also great for cutting meat and and other reasonably heavy jobs. It's hopeless for cutting pumpkin, potatoes or similar things - the wedge shape splits and breaks the food.
A Usuba - think of a rectangular shaped blade about 200mm long and 40mm high with a completely flat edge to the blade - no curve. That's the Usuba - it's the Japanese vegetable knife. It's much thinner than the Deba and it's designed for dicing onions, shredding cabbage - all the tasks you would use a chef's knife for. The difference is that you don't use a rocking motion, rather you push the blade slightly away from yourself as you slice through the food. This is the knife that you use if you want to turn a Daikon into a single wafer thin slice - the rotary peeling that the Japanese are so good at.
A Yanagiba - this is the long thin sashimi knife - yanagiba roughly translates as "willow leaf". The blade is anything from 210mm to 330mm long. The food is cut with a long drawing motion using the whole length of the blade. Ideal for wafer thin slices of fish for sashimi or for thin slices of that boned leg of lamb.
None of these knives is made for cutting bones. The Deba is OK for fish bones but nothing more. Because the steel is so hard the blades are prone to chipping if you cut bones or frozen food. Similarly twisting the knife in a cut is a great way to create unhappiness as the beautiful knife blade snaps.
Traditionally these knives are made of either high carbon steel or a lamination of high carbon steel with softer steel or iron. The softer steel supports the hard but brittle high carbon steel. The problem is that high carbon steel is prone to rust. You have to keep the blades washed and dried and you have to clean off acid foods promptly - things like tomatoes and lemons are anathema to high carbon steel.
Many manufacturers now offer traditional blades but using stainless steels. The traditionalists argue that the edge taking and holding characteristics are not so great as high carbon steel. I suspect that most of us would be hard pressed to tell the difference.
Now the hard bit. Japanese knives are brilliant to use in the kitchen, they glide through food, creating wafer thin slices and barely seem to pause on difficult-to-cut foods such as tomatoes. You do have to sharpen these knives however. If you buy a "westernised" Japanese knife like a Global then they will offer you a sharpening system tailored to the knife. However if you want the real experience of a traditional Japanese knife you have to learn to sharpen it. You can't use a knife steel or one of those sharpening wheels - you really do have to use Japanese water stones. Most home cooks would use a 1000 grit and maybe a 4000 grit stone. The 1000 grit is for normal use and the 4000 grit polishes and refines the edge to give it real sharpness - that painless friction-free cutting ability which ensures the knife reaches the bone before you feel the cut!
The bevel is sharpened at the required angle of 10 - 15 degrees - you just follow the bevel that the manufacturer has cut. The back of the knife is then flattened on the stone. As you sharpen the bevel you will feel a little burr forming on the flat back edge of the knife. You put the back flat on the stone and work it until the burr has gone.
Is it easy? Not really, but it's not that hard.
Using Japanese knives is a sublime experience, cutting food takes on an almost Zen feeling.