For reasons best known to themselves (i.e. they haven't told me), gear-maker Baladeo recently spun off a small company called Deejo in France. Deejo's products (at the time of writing) are a range of ultra-light knives in three different sizes. These were mentioned in Matthew Pullan's report on ISPO 2014 in Germany, and given their very light weight and minimalistic construction it seemed we should take a closer look at them.
Basic Technical Details
Deejo knives come in 3 sizes: 15 g, 27 g and 37 g, and in 3 styles which they call Naked, Colors, and Wood. Not all combinations exist. All three weights exist in the Naked series, while the colored ones are all 27 g and the wooden ones are all 37 g. We received a 15 g Naked knife and a 37 g Wood knife for review.
In addition there are sets of knives in black flocked lined boxes: suitable for gifts maybe. We didn't go that far.
There are three sizes of knives in this range. The 15 g knife claims a 55 mm blade, the 27 g knife claims an 80 mm blade, and the 37 g knife claims a 100 mm blade. These lengths also apply to the other series. The measured lengths of the cutting edges for the two we received are 54 mm for the 15 g unit and 94 mm for the 37 g unit. The 37 g knife is 100 mm blade from the tip to the centre of the pivot (making the knife just 'street-legal' in Australia). (The 3 plain photos are from the Deejo web site.)
The Naked Series, 15 g, US$26.43.
These little ones consist of little more than two flat bits of metal, plus a pivot. The blade locks open against the small round peg visible below the pivot; it is kept open by the blade of metal labeled 'Press'. This rather cunning and almost invisible mechanism applies to all models, and will be explained later. The handle in this little one has a hole at end for a string loop; fairly thick string is provided.
15 g knife in hand.
As you can see, the 15 g knife is quite small. Well, at 15 g, what did you expect? The loop of string can be seen at the end of the handle.
The Colors Series
The Colors series, 27 g, Red.
This series features a thin strip of colored polycarbonate along the handle, where it provides some protection for the cutting edge against the world - or vice versa depending on your point of view. There are lots of bright colors available: I won't list them all.
It may be worth noting that polycarbonate is an extremely tough plastic. I don't think there would be any chance at all of the plastic breaking. It is held to the handle by three little Torx screws, which are sized to not stick out at the back.
The Wood Series
"The Wood series, 37 g, Rosewood, US$42.71".
Here the plastic protection strip has been replaced by some good (genuine) wood: you have a choice between Rosewood, Juniper Wood and Granadilla. These are the sorts of woods you might find in good wooden-handled knives: tough, fine-grained and not particularly susceptible to water. Again, three Torx screws hold the thin strip of wood to the metal handle. In this case there is also a 'belt clip' on the back of the knife. A light soft black fabric bag comes with the knife.
37 g knife in hand - light, but a decent blade.
The blade length for the 37 g knife is quite respectable and useful, although with such a light handle there would be a limit to how much force you could put into the cutting edge. An expert would say to substitute skill for force of course. I will add that all three sizes have extremely wicked points.
The presentation boxes, magnetically stuck together.
All single knives come in presentation boxes as shown here. (The sets come in more glamorous black boxes.) What is not obvious is that there are small magnets in the sides of these boxes, so they can be stacked up on the shop counter in high towers with the curved plastic covers facing the customer. They are somewhat Lego, but very fancy.
More Technical Details
The 37 g units have a symmetrical grind (i.e. both sides) to a 1.9 mm thick back. The major grind is ‘hollow’; while the edge grind is flat (this is normal). The little 15 g units are different: they have one dead flat surface and one ground surface, and the back is 1.7 mm thick.
Lock pin (red) and friction dimple (blue).
All the knives have a lock pin to limit their opening. This is shown here on the 15 g unit by the red dot. It is solid. There is also a dimple on the end of the spring, pointed to by the blue line. We will come back to that shortly.
The small dimple shown before seems to be there to control the alignment of the spring with the blade. It spans the thickness of the brass washer at the back (see below).
The liner lock trick.
When the blade opens fully, the end of the blade at the blue line just clears the part of the handle labeled 'Press', and that strip of metal pops up against the large pivot to lock the blade open. To close the blade you press down on the 'Press' label so the strip clears the blade, and then the blade can pivot towards the shut position. This is shown in the lower part of this illustration, where I have just started to close the blade. The blade just overlaps the liner lock spring by a millimeter or two in the photo.
The small dimple shown before on the 15 g unit seems to be there on the smallest of the range to control the alignment of the spring with the blade. It spans the thickness of the brass washer at the back (see below).
What is not shown in any of the photos is that there is a small thinning half way along the strip of metal marked Press: that is where a lot of the spring bending takes place. It is not a 'defect' in the stamping.
The large cap on the pivot in the above photo hides a brass shim - there's one on the other side as well. The brass makes the blades rotate smoothly: otherwise the metal surfaces could gall and drag. It's a small detail, but an important one for long life. Since the blade rotates about the pivot, the (stationary) cap at the back is smaller. Ah yes: keep the pivot clean and lubricate occasionally very lightly for best performance.
The 37 g knife has a belt clip. It is visible in the top photo in the last illustration. I don't want or like a belt clip, so I inquired about removing it. Possible, was the reply, but not advised. It helps to stabilize the pivot, and the screws have their length set to include the clip. Well, hum, maybe one day I will 'modify' the clip to keep the bit at the pivot and remove the rest.
One caution was mentioned: Deejo has carefully adjusted the tension in the pivot screw to hold the blade securely but let it open smoothly. If you undo the pivot screw it may be tricky getting the right torque when you reassemble the knife. I image 5 minutes with a Dremel or some sort of grinder might be an alternative.
Obviously what sort of steel has been used is important. Some Deejo literature says they use 420 Stainless Steel; other literature says the blades are 2CR13 stainless steel hardened to 52-54 Rockwell while the handle and clip are 2CR13 hardened to 45-48 Rockwell. I enquired about this but got no answer. Checking on the web showed that '2CR13' is simply the USA designation for 420 SS: it's the same stuff. The steel in the screws and pivot is not specified. What is 420 SS steel? I quote:
420 SS is a general purpose medium carbon straight chromium high hardenability martensitic stainless steel with good strength and fairly good corrosion resistance. It is generally supplied hardened and tempered. Due to its excellent hardenability it is capable of being through hardened up to Rc52 or higher depending upon carbon content and section size.
I tested both knives at shaving the hairs on my arm. That is a 'standard' test for a knife blade (or axe blade, or machete blade - whatever). I found maybe 1/3 of the hairs were cut off at the skin surface, with some drag. That is not bad, although I can get a better shave from my 400 mm long 6 mm thick (16"x1/4") Brades machete manufactured in the UK about 1900, but that one is some very serious carbon steel. It is also rather heavy! Whatever it hits stays down.
The Deejo blades are not the hardest steel used in knives. For instance, the blade in the Benchmade 530 is made from 154Cm steel, with a hardness of 58-60 HRC. The Benchmade knife is on the other hand a lot more expensive - up around $100 or so.
If you explore the MyDeejo part of the Deejo website, you can find some interesting variations. You can have the surface of the steel either shiny or with a 'titanium' finish. Exactly what the 'titanium' amounts to I am not sure, but it comes out rather matt grey. The sharpened edges do shine normally. Then you can have a 'tattoo' embossed on the blade if you want: they were offering a somewhat elfish-looking tree and an owl when I wrote this. Finally, there seems to be an option of having some writing on the handle, but this option was not functioning when I looked, so I don't know what that is about.
The little 15 g knife is actually rather convenient in my pocket. It is small and unobtrusive, and sharp enough for most any tasks I have given it. Basically, it serves as a useful pocket knife, and blow Crocodile Dundee. The edge of the blade is close enough to the handle that it does not catch on other things in my pocket, so the design seems to work.
The larger one is about the right length for carving up loaves of bread, blocks of cheese and French sausage when walking in Europe. I did not try splitting firewood with either Deejo knife - if the wood is dry I just break it. Anyhow, I seldom light a fire. The wood trim on the unit tested is quite effective at guarding the edge of the blade, and the wood seems determined to last. I could carry this larger one in my pocket - with some minor difficulty, or clipped to my belt - if I wore a belt. But I don't trust things clipped to my belt, so that is unlikely. But being inconspicuous has its own advantages.
The blades seem to hold their edge reasonably well. The steel is not as hard as is used in some more expensive knives, but it is quite hard enough for ordinary use. Resharpening is not difficult: best done before the blade gets too blunt and do it with a fine stone.