Knife Review: Viper Twin

In this Viper Twin review we will be taking a detailed look at this new knife. The Twin is a small and elegant slipjoint gentleman’s pocket knife, especially suitable for every day use. It was designed by Fabrizio Silvestrelli who has been collaborating with Viper for years in the development of new knives.

Each of the Twin’s handles are made from one piece of titanium formed into the body, liner and bolsters, making it very strong, and it is offered with a choice of different colours of scale inserts. You can choose from Dark Matter Gold carbon fiber and the ivory G10 or as shown here, the green Canvas micarta. The Twin also comes with a leather slip case.

The blade is made from M390 stainless steel, an excellent combination of edge retention and corrosion resistance. It is non-locking slipjoint design, and the cutting edge is under three inches long making the knife friendly carry in many places.

What’s in the box?:
This is more of a ‘what would have been in the box’ as I don’t have the box. This knife was a display piece at IWA 2024, so you may see a few marks that would not be there on a new knife, and I have only the slip case and knife.


A good look round the Twin – Things to look out for here are:

This gallery is quite a large one, covering all the main aspects of the Twin. Starting with a detail of the pivot bolt in the integral bolster, moving to the other end of the handle with rear integral bolster and lanyard hole. The spacer/back-spring of the Twin is polished making for a stand out feature next to the matt titanium. The fit of the handle scale, and the one-piece construction of each titanium handle can be seen. My personal preference of phosphor-bronze washers are used for the blade pivot.
Swinging out the blade, initially to the half stop. A drop-point with long swedge gives this a powerful look. Focusing in on a few smaller details on the M390 blade, and into the handle. The final image is of the blade tip with factory edge.


The Blade and Handle – Detailed Measurements:
For full details of the tests and measurements carried out and an explanation of the results, see the page – Knife Technical Testing – How It’s Done.

The blade is made from M390 steel.

Being a slipjoint, the blade’s resistance to opening and closing is a key feature. One of the Tactical Review’s tests is to measure the torque required to open and close the blade, and in here including the half stop. This is done using a force meter and applying it to the blade at a set distance from the pivot.

The final measurements are as follows. A crucial factor you can see in these results is that the closing force is significantly higher than the opening force, making the blade stable during use even though it is non-locking.


The Factory edge up close:

Followers of Tactical Reviews will know my views on factory edges, but to recap:

Anyone using a knife will need to sharpen it. That first factory edge is just like the first tank of fuel that a new car comes with (or first charge of the battery).
A good factory edge is a ‘nice to have’ but not a ‘make or break’ for a good knife, as you will be putting your own edge onto it soon enough.
The factory edge does however indicate the care a knife maker has put into the final finish.
It is for this reason Tactical Reviews measures factory edge sharpness and specifications, and includes this information in the detailed technical testing.

As a further look at the factory edge, this section has been added to include some high magnification photos of the factory edges.

There are a few more images than I normally include as I found this knife, despite being a show knife, still had some burrs from the factory sharpening. A quick strop would remove them quickly and this edge was very good, so this is out of interest more than anything else.


What is it like to use?

As a non-locking knife I’m able to properly EDC it, and have been carried this knife for a considerable time. My nails don’t like nail nicks, and I always pinch-open the blade of the Twin, which is reassuringly firm in its action. The size is both easy to carry but also substantial enough you don’t feel it is lacking, certainly not for typical EDC use. The wide flat ground blade makes light work of various jobs and slices well.
This gallery shows it in my XL glove-size hands.
In the last two images in this gallery (one of which is included full size at the end of the review) you can just make out the modification I have made, which for me completes the Twin, and that is adding a sharpening choil. I find that small point detail incredibly useful when I’m doing certain cuts so I’ll often add this feature if it isn’t there.


You might have noticed the review ‘feature image’ makes the blade appear very dark, and then in the review introduction, another similar image with the blade full of light. And just below here is another version somewhere between. Of course the blade is very reflective and the changing light gives very different character to the blade. Though the feature image is absolutely real, it is not really representative of how you see the Twin most of the time, it was however striking and interesting looking, so I put it as the headline feature image for that reason.

With the minor modification I made (adding the sharpening choil), the Twin is a firm favourite of mine and will be difficult to displace from my daily EDC.


Review Summary

The views expressed in this summary table are from the point of view of the reviewer’s personal use. I am not a member of the armed forces and cannot comment on its use beyond a cutting tool or field/hunting knife.

Something that might be a ‘pro’ for one user can be a ‘con’ for another, so the comments are categorised based on my requirements. You should consider all points and if they could be beneficial to you.

_______________________________________________
What doesn’t work so well for me
_______________________________________________

No sharpening choil (but I added one).

_______________________________________________
Things I like
_______________________________________________

Reassuringly firm blade retention torque.
Stable construction.
Polished back-spring detail stands out.
M390 steel giving excellent edge retention.
Slim and easy to carry.
Strong wide blade.
Leather slip case included.

Review Videos

Starting with a short format sixty second review:


Onto a full video review covering many more details:


 
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Knife Review: Viper Tecnocut Dan 1 and Dan 2

Could the Dan (1 and 2) by Viper Tecnocut be the perfect EDC knife? It was during a meeting with Tommaso Rumici (the designer of the Dan) about a completely different fixed blade design of his, that Tommaso produced a Dan 2 from his pocket and handed it to me. We were still talking knives, but now onto something very different. Intended as an easy to carry, and as widely ‘EDC Legal’ as possible pocket knife (due to size and lack of a lock), the Dan gets so much right, it was an instant hit with me. Since then I’ve not been able to put it down. In this review of the Viper Dan 1 and 2, I take a very close look at this knife and why it works so well.

A few more details:

What’s in the box?:

The two knives in this review were provided without packaging or any accessories as they came directly from the Viper Tecnocut display stand at IWA 2019. This also means they have been handled and ‘played with’ by hundreds of people during the show, so might not be in perfect condition.

A good look round the Dan 1 in Zircote Wood – Things to look out for here are:

As you take in the details the quality of finish is clear, along with how sleek and efficient each of the design elements are.


A good look round the Dan 2 in Burgundy Canvas – Things to look out for here are:

Getting a sense for the different handle material, but the main difference is the wharncliffe blade of the Dan 2.


Explained by the Maker:

As I mentioned in the introduction, while at IWA 2019 I had the good fortune to both be introduced to this knife by, and able to talk about it with, its designer Tommaso Rumici.

Tommaso presenting the knife to me:

Rather than repeating the explanation, I’d recommend you visit Tommaso Rumici’s write up of the Dan here, where Tommaso gives you the background story of this excellent knife, including where the name came from.

With kind permission from Tommaso, here are a couple of his concept design sketches for the Dan.


The Blade and Handle – Detailed Measurements:

For full details of the tests and measurements carried out and an explanation of the results, see the page – Knife Technical Testing – How It’s Done.

Take note of some results, like the rolled cutting edge length, and thickness behind the edge, which are particularly relevant when comparing the Dan 1 and 2.

The blade is made from N690 steel.


What is it like to use?

It’s a really unusual design, being a cross between a friction-folder and a slip-joint. The Dan can be opened two-handed, or one-handed and although the opening/closing torque of the slip-joint mechanism is nothing to write home about, the protruding tang sits nicely under the thumb allowing you to hold the blade open.

This knife (either blade style) has actually converted me to pocket clip carry. Before ‘Dan’, I had not found a knife/clip design I felt comfortable with. It HAS to be deep carry, sticking up above the pocket edge is no good (for me). Then there is the clip and handle texture combination. My biggest complaint is how vicious most knife clips, particularly the underlying handle surface, are to the pocket material and edge; way beyond the need to hold it in place, and in some cases almost impossible to fit it onto the pocket or get it off again. If you like ripped pockets, great, but not me.

Instead the Dan (both handle materials on test), has the deep pocket carry clip with a clip spring strength that holds, and has not let it go astray, yet is easy to fit and remove. The handle material finish is smooth without being slippery, so provides some grip but is not overly abrasive to the pocket material.

I’ve been carrying this knife daily for 9 months now – pocket clip carry – totally unheard of for me.

Using the short tang (shorter than most friction folders) to open the knife one handed does require some care and concentration as it is very easy to turn the knife into your thumb pad (as ably demonstrated in the photos) and have it bite you. It does require a determined and positive approach to keep from cutting yourself.


Is it perfect? Clearly, as I’m about to show, for me it is not quite there, as I have made a couple of small modifications.

However the initial inspiration for this modification was entirely due to UK EDC carry law – a cutting edge less than 3″. Proven by many cases, this is typically a measurement of the cutting edge being rolled along a ruler, not the straight line measurement. With its sloping back handles, the Dan also has a longer cutting edge than blade length. Combining these factors, the Dan 1 falls foul, by 3mm, of the UK EDC legal carry requirement. I decided to rectify this with a Dremel and remove 3mm of cutting edge while at the same time creating a sharpening choil (which I prefer anyway).

With the success of the Dan 1 modification I decided I needed to do the same to the Dan 2 though this did not have the same EDC legal issue.

For me these are both now the closest I’ve yet found for a perfect EDC legal folding knife. OK, nothing is perfect, but these knives are superb!


Review Summary

The views expressed in this summary table are from the point of view of the reviewer’s personal use. I am not a member of the armed forces and cannot comment on its use beyond a cutting tool or field/hunting knife.

Something that might be a ‘pro’ for one user can be a ‘con’ for another, so the comments are categorised based on my requirements. You should consider all points and if they could be beneficial to you.

I’m trying something new this time and starting with what doesn’t work so well, so I can finish on a more positive note

_______________________________________________
What doesn’t work so well for me
_______________________________________________

The Dan 1 having a slightly over-long cutting edge for UK EDC Legal.
One-handed opening can be a little hazardous.

_______________________________________________
Things I like
_______________________________________________

Easy to carry streamlined design.
Deep-carry pocket friendly clip.
Ambidextrous pocket clip.
Non-locking friction-folder/slip-joint.
Widely Every-Day-Carry legal friendly (check local laws).
Choice of blade shape and handle material.
Blade tang can be gripped to prevent accidental closure.

 

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